There are different ways to help the community and the site, apart from asking interesting questions (that nobody has yet asked) and providing high-quality answers (have a look at this post, which gives you some information about what a good question is). In this post, I will enumerate some of them. (I will try to be concise so that you can more easily memorize the main points.)
Get familiar with our on-topic page. It's been updated recently (during this year) after a reasonable consensus. However, if something is unclear or you don't agree with something, please, ask a meta-question, so that we can all address that issue.
Edit posts (questions or answers) to improve them (in any possible way, e.g. to improve the titles, to correct mistakes, to improve the readability, to use more appropriate tags, etc.). I have written this post that hopefully will convince you of the importance of descriptive titles.
Flag content that is off-topic or inconsistent with the on-topic page. This not only includes flagging posts (questions or answers), but comments too. In general, useless comments should be flagged for deletion; in fact, comments are generally meant to be temporary; if you have an answer (that you think is good enough), write it formally, and not as a comment.
Vote (either up or down)! Here is a post that motivates the importance of voting. Please, read it!
If you see an unclear question or answer, ask for clarification below that post. Try to be nice (especially with new users)!
It's perfectly fine to read old posts and apply the previous four suggestions.
Visit our main chat room and connect with other people!
If you have a friend that is interested in artificial intelligence, talk to him about this site! We need more experts or experienced users, but also people that are new to AI that ask interesting questions.
Participate in meta (here) more regularly. Meta should be used to raise the issues with the main site. If you see an issue, ask a question, or share it with us.
There are posts that have not yet been updated to use latex, so you may want to do that. Here is a list of them.
(If you see other ways of helping the site, feel free to edit this post or leave a comment below).