Looking for tips/advice as a new DM

Hi! i'm a rather new DM and running a homebrew campaign for approx 4 players.

so far, we've had two sessions, and i'm unsure how exactly to maintain engagement and keep the game from sounding like i'm just telling a story.
the first session was great, however, the second... was rather dull and didnt have a lot of action. it was mostly roleplay.
Does anyone have any tips or advice on how i can maintain engagement, excitement, suspense, et cetera? and how on earth i'm supposed to write something to have all of that and keep it with smooth transitions, a decent balance of RP and combat, and generally something they'll like...

Ask your players what they want out of the campaign. I can't recommend this approach enough. Drop a little email, ask before or after a session, or any other time. If you know what they want out of the game, you can tailor it to their preferences. If they want more action, add a few extra combats. If they want tense roleplaying, add some important and complex NPCs for them to talk to, and let them resolve things socially, and not just with combat.

I completely agree with all the points Wolfe made. Overall, don't try to force anything on them, and ask them if they want something more combat based or more roleplay based.

Quote from alexxsuckslol >>

Hi! i'm a rather new DM and running a homebrew campaign for approx 4 players.

so far, we've had two sessions, and i'm unsure how exactly to maintain engagement and keep the game from sounding like i'm just telling a story.
the first session was great, however, the second... was rather dull and didnt have a lot of action. it was mostly roleplay.
Does anyone have any tips or advice on how i can maintain engagement, excitement, suspense, et cetera? and how on earth i'm supposed to write something to have all of that and keep it with smooth transitions, a decent balance of RP and combat, and generally something they'll like...

 Was the second session dull or did you just find it dull? Because those are two different things. I had a three hours session yesterday where not a single dice was rolled, we just roleplayed and everyone loved it. As the others have said ask your players what they want, communication is key, because while you may think they’re getting bored without a combat coming along every twenty minutes they might be really enjoying it. Having a decent Session Zero solves so many problems in terms of what everyone is expecting and whether you’re are looking for the same things from a campaign. 

Any reason you’ve decided to run a homebrew for your first campaign? I get the excitement of having loads of ideas you want to share but I’d normally suggest new DMs run a short prewritten campaign first because that teaches you so much about how to structure a campaign so it doesn’t feel like you’re just telling a story. Try flicking through something like Lost Mine of Phandelver and seeing how that is structured but the main thing to bear in mind is make sure you’re offering players choices. The quickest way to make something seem like you telling a story rather than you running a campaign is if you’re telling your players what to do, what to feel, how to react. You’re setting up the plot but remember they’re the ones telling the story 

Did you do a Session Zero?  If not, do a Session Zero.  Spend one full session just talking as a group about what everyone wants from the game. There are a few things you'll really want to be clear on, as a group:

1. Play style:  The three pillars of D&D are combat, intrigue, and exploration. Ask each player to score from 1 to 5 how important each one is to them. Some players just like cracking skulls and looting corpses. Some want to delve into the hidden nooks and crannies of the world to see what secrets they may uncover. And some would be perfectly happy spending an hour in conversation trying to convince a cultist to betray their cult.  The better you understand what your players want, the better you'll be able to provide them with a campaign that will satisfy their play style. Just remember that every game needs to have at least a little bit of each pillar. This gives every player a chance to really shine. One session may give the Intrigue player extra focus as they try to learn where the BBEG's hide out is. The next session will give the Exploration players the chance to follow those clues and to find a way for the party to sneak in undetected. And finally the Combat players will have their turn to tear through the enemy and kill the BBEG. 

2.  Red Flags & Red Lines:  While play style details what the players want from the game, Red Flags are things the players absolutely  DO NOT want in the game. A player may enjoy swinging their great axe through a horde of undead, but will recoil at the thought of an innocent child being hurt. That's perfectly normal. This is, after all, a fantasy game. Many people play this game to escape some of the harsher realities of our world. No one should have risk emotional or psychological hardship just to play a game. Let each player be clear about what subjects they absolutely do not want to see in the game, and make clear to everyone at the table that those preferences must be respected. Some of the more common subjects may include violence toward children or pets, slavery, sexual assault, and claustrophobia. If at any time anyone at the table ever feels that one of their Red Lines has been crossed, immediately pause the game and resolve the matter respectfully.

3.  Rules As Written vs Rule Of Cool:  Some players like the nitty gritty dice math with the charts and the graphs and measuring out distances to each enemy and making sure every Concentration check gets rolled. I suppose some people also think doing their taxes is fun. Other people may prefer to only rely on the nitty gritty when absolutely necessary. Ask each of your players where they fall along that spectrum. Because it's just a matter of time before one of your players asks if they can attempt to jump off a roof, do a mid-air backflip to kick an enemy guard of their horse, and then land in the saddle and ride away on the stolen horse. There's gonna be times when they describe something they want to do, and you think that would look wicked cool in a graphic novel, but there's no specific dice roll for it in the rulebooks. You just have to find the happy medium. 

4.  This last one is key!  Snacks.  You gotta have snacks. 

Quote from alexxsuckslol >>

the second... was rather dull and didnt have a lot of action. it was mostly roleplay.

 As others have said, the word "dull" has very different meanings for different people. One point I must also highlight that hasn't been highlighted yet is that there is nothing wrong with an occasional non-action-heavy session. A long campaign isn't a huge dungeon crawl where you fight a monster in every room. I would find it dull if I knew that every session would follow the same script, even though I enjoy action very much.

But yes, as others have said, talking to your players and aligning expectations is the best way to keep it engaging and interesting for everyone.