Absolutely!
(I'm taking your post to mean you're a poker beginner as well as a wiki beginner.)
Even if you're not creating new content from scratch, you can help edit articles that are up there. You can also use the "talk" pages (for example, from
this page click the discussion tab at the top) to give feedback. It's especially important to have newer players involved in the feedback process, because it's easy to accidentally make assumptions about what your audience knows.
Also, if you play
online or at a
casino poker room, check to see if it's listed on the respective page. If it already has an article, you can fact-check it. If it doesn't, you can start one.
Feel free to send me a private message (here or there, I check both) if you have any problems finding stuff or getting started.