There are still a few online poker sites available to US players. Bovada and Black Chip Poker both still work in most states and take Bitcoin deposits. The games have gotten significantly harder in the past few years, so I would suggest joining a training site as well: either RunItOnce.com or UpswingPoker.com are probably the 2 best (I have no piece of either, used to make instructional videos for CardRunners, but they are probably a distant 3rd or worse in the way of training sites these days).

I made an AMA in the poker section of this site, been a professional poker player for 10+ years, feel free to ask any strategy questions you want in there: https://steemit.com/poker/@daut44/introductory-post-and-ama-ask-me-anything-about-being-a-professional-gambler =)