Welcome to Landroval! Sorry to hear you're having trouble getting into the RP scene. It can take a lot of patience. While there are some RPers who will only play with certain others, or certain types of characters, there are plenty of others who are more open and willing to interact with others.
Race-wise: I say play what you enjoy. An intelligent Hobbit with a fascination for jokes and puns, a Dwarf with an innate nobility and courage despite his occupation as trader, go with what you like. Personally, I favor the race of Man for RP since they seem to fit in for many situations/locations but I do occasionally enjoy my Elves for certain situations.
Class-wise: I've not found that it makes much difference in RP. I've seen fantastic thieves played by captains and LMs and awful thieves played by burgs. (Note: a great many RPers seem to dislike the use of the actual game mechanic stealth in RP; some will outright ignore anyone using it. The same goes for RKs casting lightning from their fingers, LMs having bears leap through the windows of the Prancing Pony, etc.) How you play the character seems to matter more than the class. Though if your character goes about armed, you may want to consider available weapons for each class.
It can be very hard to get into scenes. I suggest reading bios (if the characters have them), looking for characters not currently talking/interacting with another who are still giving the occasional emote, and keep trying! Sometimes, there just isn't much RP going on or everyone is doing other things. You might also look at some of the kin descriptions, not necessarily to join but to see what sort of RP you might expect from the players in that kin.
Hope that this helps (or is at least encouraging!) and welcome to Landroval!
Sorry, I'm out of clever sayings for sigs. :(