Being a dark elf has a lot of perks as a race choice and choosing to pair it with a ranger seems to be a very favorable match. Any tips on how to make it a really dominating character? How can I make her the absolute best she can be?

Make her the best she can be?  Don't be a Ranger.  If your DM will allow it, perhaps go with the Ranger revamp in Unearthed Arcana.

In all seriousness, you're probably best off going with the Gloom Stalker subclass.

Ranger isn't the best choice for a Drow, since they get an innate +1 to Charisma which is a useless stat for Rangers.  Not a huge hurdle, but it is kind of a wasted benefit.  You want to focus on Dexterity for combat and AC, and Wisdom for spellcasting and skill checks.

Gloom Stalker fits best thematically for a drow.  Typically, outside the Underdark, drow do not want to bring attention to themselves; they aren't seen favorably by other races.  They are also light sensitive, prefering to be in darkness. Gloom Stalkers are invisible in darkness, allowing them to keep out of sight, which is something a drow would covet.  Furthermore, Gloom Stalkers automatically gain the disguise self spell for free, which is a fantastic way for a drow to not draw attention to themselves.

It would obviously make the most sense for your favored terrain to be the Underdark, but depending on your campaign that might not be the best bet.

I can't really advise on what spells and stuff to take without knowing what you want your play style to be.  Are you thinking close combat, or ranged?

Ranger actually works really well and she is actually really bossed up currently just looking for some recommendations on how i can really make her shine in the role she is in. Rangers and dark elves actually work really well together since they do get dex additions as well as stealth additions.

It's not the worst combination, certainly, just not the best possible.  Racial ability modifiers can go a long way to improving your character, especially early on.  If you did Point Buy or Standard Array rather than rolling stats, they can make a big difference.

There's nothing wrong with deviating from them if it's what you want to do, and you can still make a very formidable character.  They just won't be quite as formidable as they could be if you went with a race that gets bonus' directly to the things they use.  For example a wood elf would (wood would, hehe) be a better Ranger to start, as they get a bonus to both Dexterity and Wisdom, which are a Ranger's main stats.  On the other hand, drow would make better Warlocks than wood elves would since they get a bonus to Charisma.  Wood would wood.

I'm not sure what you mean by stealth additions; Stealth proficiency would be provided by your class or background, not by your race.  Speaking of wood elves, they actually have higher stealth capabilities than drow do because of their Mask of the Wild racial ability.

Anyway, I wasn't meaning to allude that a drow ranger is a bad choice; it's just not the best possible choice if your goal is purely min-maxing. 

If it's what you want, power to you!  DnD is about having fun, first and foremost.  Some people have fun building perfectly optimized characters, others have fun building the character they want.  Neither is wrong nor bad.

I would still like to know a bit more about your character in order to make recommendations, because I don't know what roll she really is in.  You say she's already quite formidable, could you tell me how?  What fighting style did you choose with her?  What level are you currently?

try and acquire a Knaves eye patch. Great item for Drows

As mentioned, Gloom Stalker has some great choices for a Drow Ranger, since Gloom Stalkers want to be in darkness and drow get penalties while in direct sunlight. That isn't to say that other rangers wouldn't also be good, but drow are penalized so heavily by sunlight that leaning into darkness is a pretty optimal choice.

Ways to get or enhance darkness:

• Gloomstalker ranger: being invisible to other creatures with darkvision while in darkness is pretty cool. The bonus attacks and damage in the first round of combat are great as well. The 7th level feature is pretty useful if you don't already have Wisdom saves, but may not be worth going that far for... but the 11th and 15th level features also feel great. Definitely one of the superior ranger subclasses. 
• Way of Shadow monk: you get a pool of points that renew on short rests which can be used to cast Darkness, which will be valuable. The other spells granted are also really great for a ranger, especially Pass Without Trace. Higher level features at 6 and 11 are also cool, but the 17th level feature is a little unnecessary, and may not be relevant if you're playing a ranged ranger. Is not a very wisdom-dependent monk subclass, so you don't need to feel bad about taking this if you have great dex and only so-so wisdom. 
• The new Twilight Domain cleric: Right at level 1 you get to extend your darkvision to unlimited range, and remove the perception penalties that dim light normally provides, which is great for a scout character. You also can give yourself advantage on initiative, which synergizes great with a Gloomstalker ranger or an Assassin rogue. At level 2 you get a bubble of dim light as an action which lasts for 1 minute fueled by Channel Divinity; even apart from the temporary hit points the bubble gives out (which are great), being able to remove your sunlight disadvantage at a moment's notice by creating this bubble will be HUGE for a drow. You might be hesitant to splash cleric if your widsom is only going to stay at 14 or 16... but these features at level 1 and 2 are so good, that you might consider doing it anyway, and just memorizing utilitity spells with your slots that don't rely on enemies failing your spell saves. 
• Shadow Magic sorcerer: Buffs your darkvision, gives you another way to cast Darkness, and treats any Darkness cast that way as something that you (and only you) can see through. Pretty cool! But Charisma may not be a very high stat for you (despite the small Drow bump), and sorcerers don't have a ton of non-aggressive spells to use their spell slots on that won't mind about a low spell DC. The higher level buffs are cool, but probably not cool enough to splash Sorcerer with middling Charisma. 
• Fiend or Hexblade warlock: chosen subclass isn't that important, but at Warlock 2 you can pick up Devil's Sight, an invocation that will let you see through all Darkness spells or any other magical darkness effects. Being able to cast Darkness on yourself and see through it is a massive combat advantage and pretty important for any character that is going to have to live with Sunlight Sensitivity, so this invocation alone is worth splashing Warlock 2. With Devils sight, Darkness basically starts to operate as Greater Invisibility for you, as well as letting you manipulate where line of sight can be drawn on a battlefield. Hexblade will give you something to do with your bonus action other than cast Hunters Mark, let you crit on 19-20 with a melee weapon, and give you access to the Shield, while Fiend will make you a little tankier. I'd go with Hexblade, even if your Charisma is only 13. 
• Assassin rogue: doesn't care much about darkness, but gets a HUGE boost to damage in the first round of combat if you are going before the enemy. Which is something that Gloomstalkers are quite good at, so worth a mention, even if you aren't advancing through Rogue far enough to get large sneak attack dice. The free proficiency and expertise will help your ranger feel more scouty as well, or you could actually choose Scout subclass to be even better at more skills if you don't care about free crits. 
• Battlemaster fighter: very easy to splash a few levels of fighter to make yourself better at whatever you're already doing, and Battlemaster is great right at level 3 for letting you hit when it counts (Precision Attack), set up big rounds for the team (Trip Attack), or create breathing room for yourself and the team (Menacing Attack).

To put it all together, what do I suggest? 

Devils Sight (Warlock) and Twilight Sanctuary (Cleric) is just too important for a Sunlight Sensitive drow to not pick up, no matter what build you're working towards. So you're going to need 13 Charisma, and be a Warlock 2/Cleric 2. This entire post is premised on being a Ranger, so assuming you need at least three levels of Gloomstalker as well. So:

• Ranger (Gloomstalker) 16/Warlock (Hexblade) 2/Cleric (Twilight) 2, 8/20/14/8/18/14 at 20 with no feats. You'll reliably hit two targets per round with archery, be doing plenty of damage per hit by stacking Hexblade's curse with Hunter's mark, you'll have proficiency in Str, Dex, and Wis saves, you'll have the ability to see through your racial Darkness (but no extra ways to cast it). Solid baseline build.
• Ranger (Gloomstalker 3)/Warlock (Hexblade) 3/Monk (Shadow) 14, 8/20/12/8/18/14 at 20 with no feats. You'll be able to attack twice per round with archery, or up to 4 times in melee with 1d8 fists, be doing plenty of damage per hit by stacking Hexblade's curse with Hunter's mark, you'll have proficiency in all saves, you'll be able to see through your racial and monk Darkness (which monk will let you cast a LOT), and you'll have a lot of other cool abilities like invisibility, teleportation, wall running, arrow caching, etc etc etc. from monk. At Warlock 3, pick up Pact of the Tome, and take Book of Ancient Secrets as your second invocation to unlock a whole world of ritual spells that you can cast while off being a sneaky drow ninja. This would be my preferred build, but it's more of a monk than a ranger, to be honest. 
• Ranger (Gloomstalker) 4/Fighter (Battlemaster) 12/Cleric (Twilight) 4, 8/20/15/8/20/9 at 20 with two feats or ASI to spare. Focuses much more on the martial side of things with three attacks per round and lots of trick shots, but still has some very decent spellcasting with high DCs. No Devils Sight though; you could swap the Cleric for Warlock, but you'll cut your save DCs in half by doing so because it makes you M.A.D. 

Anyway, lots of ways to build it. The new UA for ranger makes them a lot better than they currently are, so if you're playing with that, that could skew things more towards the first option, but I would really prefer the second monk-based one. 

Is this for a campaign, or is this a just for fun let me theorycraft a powerful level 20 character?

This is for a campaign and I am level 5 currently i am a dark elf ranger who is hunter based and forest based

Level 5? And you went with the Hunter subclass, and not the Gloom Stalker subclass? You're Ranger 5, and you have not multiclassed yet? What feat did you take at level 4? What stats do you have 13+ in which would allow you to multiclass? 

A 1 level dip in Rogue for another skill, expertise in two skills, proficiency in thieves' tools, and Sneak Attack isn't a bad choice, and I know for sure you got the 13 dex needed (and hopefully the 13 wisdom needed to multiclass out of Ranger, otherwise your options are extremely limited)

Higher levels in Ranger aren't really that thrilling, unfortunately. Which is why multiclassing is so common for Rangers.

Just play it the way you want to play it to be honest, min maxing saps all fun out of a role playing game, role playing comes first.

Role playing and min maxing aren't mutually exclusive. Min maxing is for combat, role playing mostly occurs outside of combat. But role playing can occur in combat as well. Both in min-maxing groups and in groups that focus more on developing flawed but interesting characters.

Some groups love the strategy aspect of combat and enjoy min maxing. Other groups enjoy doing combat suboptimally to role-play the character flaws that their characters have.  It's useful if a group shares the same tendency as each other. It's helpful to see multiplayer cooperative combat with a focus on strategy as a legit role-playing arena. If you're interested in playing suboptimally, that's fine, but don't pretend like those who like min-maxing don't engage in role-playing.

Don't limit yourself by believing that one must choose between min-maxing and role-playing.

For a dark elf ranger? Well, first you want to get a pair of scimitars... :)

To be honest, just play the way you want to play; role playing comes first and min maxing takes the pleasure out of a role playing game.