IMO for someone to now make a successful career from scratch in poker meaning just paying the bills and making a living wage out of it, the
odds are stacked very high against you, although probably paying for a good coach will help you get on the right track, if like most and you could not afford a coach, I think the main rules ,would be to have the ability to learn, and to have total dedication, and I think in today's game if you had some kind of math background if only to understand the newer learning software that is available such as Piosolver and so on lol find an online coaching site, there are many about, the modern sites now teach game theory to the highest levels, I can personally recommend (Run it Once) these guys take learning poker to a different level,although its not a place for beginners imo
Before the poker boom to make a good player you needed to have natural raw skill and then to build on that, Today I think the more intelligent you are better chance you would have of joining the ranks of the elite poker players with more money than you could ever spend.
GL you will need it