If you want rep, then put out good ideas that you think other people might appreciate (in questions or answers), and then wait for upvotes! It's exactly like any other SE site -- the only difference is that the topic is "making the SE network work in the best way possible."
.....there's really no other way to do it, unless you want to try for some bounty questions.
Anna Lear recommendsrecommends (and I agree, just can't claim to have thought of it first) that one of the best ways to gain rep here is to help other users by tossing out good answers under the tags discussion and support. Doing this, obviously, helps other users the most. ( Besides the fact that answers give you twice the amount of rep that you get for questions, per upvote )