In most mmos that i've played I've tanked and dps, but never healed. And I want to give healing a try. What would be a good healer class for a beginner? A few more things I'd like to know from experienced healers out there:

1. What's my main stat?

2.What are the do's and don'ts of my role?

3.besides healing what other things will the group expect from me? That's all I could think of at the moment. Any other advice would be appreciated.