I only have two rules:
1. Buy low.
2. Sell high.
Unfortunately, I tend to break the rules often. I hope everyone else does better.
Simple and Basic, though it is better when you know how to predict when will the market gets low to execute that Buy plan, and that goes also the same on Selling plan, that what makes Trading feels like you are a CEO of your own company, you do all the complicated stuffs to earn as much money you wanted whenever you wanted.
You support yourself, you make plans yourself alone, you boss yourself around.