new DM help

Hello all, I've DMed quite a few one-shots, and some short campaigns, and I've got my first long full length campaign coming up, any tips?

Don't plan too far ahead. If you set your plans in stone, it makes your world and story less reactive to player choices/actions. You should have an idea of where to go, and enough content planned for the next session and some change, but you should approach it like every time the heroes throw a wrench in the villain's plan, the villain pivots with the changing situation, and vice versa with the heroes pivoting to react to the villain's changing tactics. 

Also, look up Running The Game by Matt Coville on YouTube-- LOTS of solid advice on that video series. 

thanks @CharlesThePlant, I'll check that out!

Is it homebrew or published? In either case, don’t plan too far ahead, but be prepared to advance early if your players find a key part of the story quicker than expected.

It'll be Phandelver and below.

There will be like 5 PCs, maybe 6.

Quote from Nanra_Taran >>

It'll be Phandelver and below.

 In that case my biggest bit of advice is read through the whole campaign and figure out ways to introduce the second half early. The book is very obviously Lost Mines of Phandelver <pause> And Below with only nothing except the location tying the two halves together. The Eldritch horrors of the second half really need introducing during the first half so they don’t come out of left field, in my case I swapped out the orc encounter for the mutant goblins and moved the mutant cow up to occur earlier, but also make sure to draw attention to the black rocks around town so players are already wondering about them when they become relevant 

That sounds good, thanks.

Yeah, I would recommend making sure you understand the whole plot. Don't set anything in stone too far ahead, plan only for the next two or three sessions at most. Keeping a little sheet of where the players are, what they are doing, and how the NPCs consider them, things like that, can be very helpful in keeping track of everything.

Plan 1 to 3 weeks ahead but no setting anything in stone 

Use foreshadowing as best you can…