revan07, welcome and thanks for posting your questions here. You've come to the right place.
1. To get more stars, you have to post more messages. In the beginning, it's easy for the stars to add up. As you post more, the gaps between one star to the next get greater and greater.
2. Karma is added or subtracted to help share with the community how some people are exhibiting good (or bad) behavior. It's a simple way to say thanks, or no thanks, to individual posts and their author.
3. Moderators can remove karma points if it's considered abusive. But, if members are within the posted rules of this forum, they don't necessarily need to be Star Wars fans. If a member is only being negative, you can press the flag icon beside the post (not karma) and a moderator will be notified with a report.
Founder/Editor, BFFC
aaron@bobafettfanclub.com