In a bull market, don't cut your gains short.

In a bear market, don't hold on too long.
Buying requires patience.
Selling requires determination.
During a bull market, avoid panic selling.
Don't chase after early gains; if there's a big dip in the morning, just add to your position.
If there's a big rally in the morning, reduce your holdings.
If there's a big rally in the afternoon, also reduce your position.
If there's a big dip in the afternoon, buy the next day!