I wouldn't worry at all about "getting on peoples' nerves" and whatnot, as the parts of the Guild community worth interacting with are very chilled out, though some will give you the "I'm super duper nice but I can get really mean so watch out buster" spiel. If you can get past that cringy nonsense, you'll find yourself a natural fit. As for the other parts of the community, well, they're easy to identify and ignore. 

Aside from that, I'll tell you what I tell every new person: See those little descriptive blurbs below the section headers on the main page? Fuck'em. If you're even halfway decent at writing and can play a character well, you can get in any RP you fancy, be it Free or Advanced, provided of course the GM isn't just garbage, but that doesn't happen much. Just say hello in the Interest Check or OOC to display your interest, and then throw down your character.

You'll make up for your newness naturally with time by interacting with people in OOC, and you'll build up your reputation with good IC posts.

Oh, and a fair warning, a lot of the people on this site are uh...sensitive. Not saying to walk on eggshells, but just be aware that you might end up saying something you think is innocuous but sends someone else into a flaming, impotent rage.