Money Management: You must make your trades as fixed as possible. Trade with the same risk, capital, units, percentage, and in the same type markets to manage risk most effectively.

Methodology: Choose a method that works for you and your personality. (Dow Theory, technical indicators, patterns, price and volume, etc) Once you have a methodology to your trading, test it in the real world, in real time, either with micro trades or paper trade. You need a sample size to judge its efficacy.

Trader Psychology: Manage your hope, greed, fear, and pain to stay in the game.