I did a bunch of Tweets on D&D for ex-DiSers the other day - enjoy or don’t:
Character creation: note that Abilities hit a new + on even values so a 14 is the same as a 15. Having one 18 will make your character powerful and generally you can do with non-humans.
On the other hand, if you pick a variant human (little box on pg 31) then you get a feat in which case Lucky is your go-to as long as you remember to use it when you get a terrible D20 roll that looks like it might put you in hot water!
There are a lot of backgrounds but most are actually pretty uninteresting. Look for one that gives you skills your character class doesn’t let you pick or ones your character class has that you want but you don’t have enough slots to pick.
Stick to Neutral Good, Chaotic Good or Lawful Neutral align.
If you’ve already got a character sorted then concentrate on remembering its skills for combat (I am TERRIBLE at this still). Can help to write them up in a sort of crib sheet.
Remember you can split your Move around your action and if you can use your bonus action then do.
Tactically everyone can only make on Reaction Move per round so that means if an enemy already did an Opportunity Attack you can move past them freely during your turn without provoking one.
if you can’t think of anything to do either:
- go ‘full defensive’ so attacks against you are at disadvantage
- ready an action, like ‘shoot if I see a bad guy appear’
Some people will be cool and some will be dicks. Some people find their inner-dick playing D&D or just play their character very well which can mean they’ll piss you off but it’s important to make sure they’re not just playing their character reacting you yours, not YOU.
Which basically boils down to me tending to only play agreeable characters because it’s easier but you do often get people getting in a bit of a mini strop because they think a player is being an arsehole not their character. Although obvs some players are arseholes 
In general stay focused when you need to be. Like there are times when you can chat while other characters are doing stuff but when the DM is delivering a monologue about what’s happening best to let them finish rather than disrupt flow with Qs but most DMs make their rules clear
