As far as Poker goes (at least for Texas Hold’em), I’d recommend sitting at a low stakes table (1/2 no-limit is the lowest most places have) and merely being observant/make casual conversation at the table for a while until you feel comfortable. If you’ve never played, just tell the dealer and they’ll be happy to help you out (most players will notice if you haven’t played before anyways so you’re not really at a loss there). Just play “tight” (a small range of strong starting hands) and that’s a pretty good place to start!
Research individual companies in your desired niche: If possible, it’s always better to become an affiliate directly with a company (if they have an internal affiliate program), as no one else will be dipping into your commission rate. This is the preferred route for most of the prominent affiliate marketers, including Pat Flynn. Unfortunately, it’s also the most work, as you’ll have to do the research yourself to see who offers programs (they’re usually listed in the website footer).