Don't think one thing can cover life lesson, but here's mine of many things:
1. Live simple.
2. Hack your life.
3. If you are successful, stay low profile, if not, stay high until you make it.
4. Don't think too much, if something you feel worth to do it, just do it, and always ask what's there to lose anyway?
5. Don't think of step 2 until you done step 1, because step 1 outcome determines your step 2, and doing this help you to do reality check.
6. Whatever you do, give deadline and timeline because anything that worth doing has time limit.