The list below is an extended version of the answers from this post and it is meant to contain easy to copy comments for new users.
Welcome to Mathematica.SE! I suggest the following:
- As you receive help, try to give it too, by answering questions in your area of expertise.
- Take the [tour] and check the faqs!
- When you see good questions and answers, vote them up by clicking the gray triangles, because the credibility of the system is based on the reputation gained by users sharing their knowledge.