You need to get educated on the markets, methods, systems, psychology, and your own issues. You need to find a method that fits your personality.
You need to be adequately capitalized. If you are undercapitalized it will amplify all kinds of psycho problems: fear and greed.
You need to have realistic expectations. You are not going to get rich quick in this game. Most successful traders have blown out at least one account.
Once you learn enough, you will need DISCIPLINE to implement what ever strategy you have chosen. You will need discipline to trade through all the emotions you will most likely feel.
I would recommend going with a prop firm so you can avoid all the stupid mistakes there are waiting for you to make, and try to find a mentor. I don't have any recommendations on a particular firm, but if I was starting over I would do this primarily for the education.
Use the search function on this site, answers are here, whether these answers will work for you is another matter. Be prepared for lots of cynical, smart ass posts throughout the threads. That is just part of the culture here.
Good luck, and if you are serious about this game you will need perseverence.