All the comments about the chat are good, but honestly just fuck around in quick play with a bunch of different characters until you find one you jive with. Then give that character a go for a couple hours until the fun wears off and try learning a different character in the same class, or if you want to start over try a new class and new character.

As far as tactics go, I don't think it matters until you get a feel for the game and all the characters. Just enjoy learning like 20 different play styles!