Keep your mouth shut
Make sure you can trust your associates
If the going looks foul, lay low and wait.
Never spend more money than you can afford to lose
Keep track of your money
Always have an exit plan. The people who get in and get out quickly before the heat builds up are the ones who stay out of jail. The longer you operate, the more vulnerable you get.
Don't do anything to attract attention to yourself
If it sounds too good to be true, it probably is
Never trust a thief
Any other suggestions from people?
Expect/anticipate that any time money leaves your hands you might not see it/the product ever again. If a vendor decides to fuck you, or a market goes down with your coins, it shouldn't ruin you. This is a good rule to live by in general.
both very important rules to live by.