1. Trust good character more than promises.- Diogenes Laertius, Lives of Eminent Philosophers,
2. Do not speak falsely.
3. Do good things.
4. Do not be hasty in making friends, but do not abandon them once made.
5. Learn to obey before you command.
6. When giving advice, do not recommend what is most pleasing, but what is most useful.
7. Make reason your supreme commander.
8. Do not associate with people who do bad things.
9. Honor the gods.
10. Have regard for your parents.
One things I find remarkable about Solon (638 BCE - 558 BCE), other than the fact that when repealing the laws of Draco he re-wrote Athens Constitution in poetic verse (in 594 BCE), making him the first person in history to formalize democratic principles in government, is that after doing so he went into self-imposed exile for ten years to ensure that he would not become a tyrant.
For a comparison of these commandments with the Biblical Ten Commandments, see Richard Carrier's Secular Web essay, "The Real Ten Commandments."