Becoming a professional poker player is in fact very similar to becoming a professional trader, it is important to learn the skills necessary to profit from the activity but it is also very important to learn money management skills, and we know this is the case because there have been many cases of poker players that have an amazing ability to play the game but which they do not know how to manage their money effectively, and this means that their poker skill level becomes irrelevant and they also become long term losers.
Both are almost the same as professional poker players and professional traders are required to learn more from others, but the subject matters set them apart. But both must have good self-control so that they don't get out of line and still be able to play poker or trade well. And I agree that money management is also very important for every gambler because this will determine how much money they will use to gamble.
Learning from others could be a good way to start becoming a professional but then I sometimes prefer to learn from my past mistakes, this will allow me the time to thoroughly analyze my mistake and make valuable adjustments against future occurrences.