1.      
1. Do your handicapping for yourself.
2. If you can’t take the losses don’t bet.
3. Greed Kills.
4. Winners correct their mistakes next time out. Losers bet bigger trying to cover…which will never cover in the end.
5. Never get too high or too low.
6. Scared money don’t win.
7. Women and booze don’t mix with horses.
8. Don’t bet a beaten favorite coming back trying to do something he has never done before, anything.
9. Every time that gate opens, expect to be humbled.

from the ever insightful Randy Parker. Make sure you check out his excellent Macroeconomics Blog (in his site he may talk a big game but remember that he's a degenarate degenerate horseplayer like yours truly).