I'm no Warren Buffet, but these are rules I usually follow:
1) Buy stocks you know
2) Buy stocks $10 and above
3) Buy stocks that pays you to wait (dividends)
4) Buy stocks you think you can own forever (and not based off spikes)
5) When your stock falls 20% or above, average down (unless the fundamentals have changed drastically)
I'm sure there's plenty of holes you can find. But they work for me.