Lurking is probably what you're doing now. It's just hanging around, reading articles, following threads and getting to know the wiki and the editors. You can lurk for as long as you want; you don't have to log on or edit anything.
If you've got the interest, intelligence and time to lurk though, it's likely that you could make worthwhile contributions.
Don't be reluctant to edit — your point of view or special knowledge will be respected no matter how
stupid different from (to?) that already here.