Hey all, last Saturday I ran my first real game of D&D, using Lost Mine of Phandelver, for three friends, all of whom had never played D&D and only one of whom along with me had played a tabletop rpg before. It went pretty well, everyone had a lot of fun and we're looking to play it again real soon (probably with some other friends as well who couldn't make it on Saturday).

So now I'm looking for any tips and tricks to help me be the best GM I can be and provide the best experience for my players. What should I avoid, what should I keep in mind, how should I prepare for the next game?

The best advice I have ever gotten

 All of Matt Colville, like the link Sposta provided and DM/GM tips on Geek and Sundry by Matt Mercer/Satine Phoenix are great places to start. It would be much easier to ask specific questions considering the format of the message boards rather than asking for "tips in general" here.

I'll check those out, it's kinda difficult to think of specific questions though, since lacking knowledge or experience as a GM I don't really know what I'd need to know. :P One thing at least, what are some things I should prepare outside of the starter set rules manual, like, what are useful notes or materials to keep at hand because going through the books took up a decent chunk of time.

I always find myself preparing the adventure itself too much, and then someone asks me what the village looks like and I realize how little I prepared for those simple things. If you can describe all of that extemporaneously its less of an issue until your players remember that you described something differently the week before. Don't forget that the rest of the world exists.

Challenge both your Characters and your players

Falling damage is 1d6/10ft

Players should be somewhat responsible for their own race/class features and spells

Anything else can probably be solved with common sense and logic, and then look it up for next time if you need to stop for more than 3 minutes to look stuff up.  

Keep the game moving. Like Sposta said, don't get bogged down in rules minutiae. Use what you know, common sense, and a dash of "this sounds cool lets try to make it happen".

If you struggle with visualisation or memory, find pictures of NPC's and locations and print them or put them on your phone/tablet. You need a musty old library? Just google it. Then you can describe it in as much detail as you like. This obviously doesn't work for EVERYTHING, but most locations or people aren't that specific that it doesn't work.

This will probably take over your life. So get your players to invest in some good backstory so that you can develop the plot beyond Phandalin and weave their stories into it. It's not about overplanning, just giving you more to work with in the long term, and also helps to engage your players.

RP! It's fun! Campfire stories can be a good way to get people to engage as their characters. Encourage people to speak as their characters, rather than "Phinian says"....". No, just say it. Voices are a lot of fun, but obviously some people are more or less confident with that. Sometimes it's easier to think of a fav movie character and model your voice after that. It can help keep it consistent.

Puddles gives some great advice. The backstories especially. I currently have players complaining that their characters have no hook into the adventure, they are the same players that still haven't given me their characters' backstories after me asking 5 times and we are about to start session 2. (insert eye-rolling emoji here)