Hello Aledore, and welcome to Argent Dawn! I hope you will enjoy your time on this realm!
For advice for new players, you can check out Acrona’s Argent Dawn Roleplay Compendium in the stickied post. It has information about finding roleplay, hubs, and the like.
For Alliance vs Horde, I personally very rarely log in on Horde characters, so I cannot really say what the RP situation is there. From what I heard, the Alliance is more numerous and Horde RP is more guild/event oriented than having persistent hubs like Alliance RP does, but don’t quote me on this. Ultimately, I think it’s best to just play whatever race you want to play; you will find RP either way.
As for RP tropes to avoid, there’s a long thread on red flags in RP, but personally, I think it’s best not to overthink it and just learn by doing. Ultimately it’s about what kind of character you want to play, rather than what others want you to play. As long as you’re respecting the lore and the other players’ agency, you should be all right.
So think of who you want to roleplay, create your character, and I hope to see you in-game sometime!