Hello Ann-e I would say that there is a lot of activity in Kumo and Kiri because of the war going on, so if you were to join a "crew" I would probably pick one of those villages. Iwa and Suna need more members, and Konohagakure is usually a steady choice.
As for qualities that people look for in a good character and partner for roleplay, I would say these are the top qualities:
1. cooperation: I mean the essence of roleplay is cooperative story telling, if it turns into a game of "I did this, no you did not" it's not fun for anyone.
2. no showboating: Everyone's an individual snowflake, so play your character to their flaws as much as their strengths. it is actually kindof fun facing off against people who are much stronger than you are and having them teach you via their experience.
3. a great attitude. If you go into every thread with the attitude that you're going to learn something new about someone's character, I would say that's a winning quality.
Have fun on the site and I hope to see you around sometime, either in the chatbox or whatever village I happen to find myself in.