Well! Let me first direct you to the Academy . In that group you can request a mentor to help you with roleplaying as well as various writing exercises that can also help you improve ^.^
From there you could check out Roleplay 101 then try your hand at Jump-in roleplays -nods-
Well, I'm Celest! Feel free to ask my any question. I'm normally around.
I'm Selenite, pleased to meet you!
Tetsu and Celest already gave you awesome links to check out...
Other than that all I may say is just relax, look at what others do and let your creativity flow!
Here, have a cookie whilst you get inspiration from your muse!
Welcome to Iwaku, Evi~ I understand you're new to role playing and stuff, but we have lots of newb approved role plays in the Jump In Thread. This is where you can role play with other players without submitting a bio or signing up! The Academy, like Celest gave you, is also a perfect way to start things off!
If you need any help navigating around the forums or something else in General, give us Blue people a shout! :D