My experience with tabletop RPG has been extensive. My experience with online is relatively very new, but I really wanted to experience it. I am by nature a shy person who becomes very social with people I am comfortable with. A few months ago, I forced myself to turn on my roleplaying tag and keep it on most of the time, just to show that I'm interested and open to it. Most of the time if I'm in a strange situation (Pocket D, other places I don't know anyone) I will sit and watch and listen to other people's conversations to pick-up on things I like/don't like [My main RP character also has some degree of (back-storied) social awkwardness] I've also gotten great lessons from people who are very good at it (shout out to Crystal Dragon). I have become much more comfortable with it [and no, I am by no-means an expert, but I'm beginning to better understand what I don't know], and I'm having much more fun in the game than I ever have.
So my advice for people who are new at it, or who want to try is: observe, listen, ask questions. If you see a good scene, but don't want to interrupt it, maybe send a tell to one of the participants afterwards telling them that you liked it (people like to be praised) and then ask them if they have any advice to give you. Most people who RP, if they have time, are willing to help you or at least willing to point you to somebody who can. Also RPers do want more RPers
So again, don't give up, it can be fun and rewarding and definitely worth it.