Jason Goldberg has a great post on some of the things he learned while CEO of Jobster.com.

1. The CEO's job is to create value.
2. Try to ride some powerful existing waves vs. just creating new waves.
3. Technology companies are all about the product.
4. Related to #3, the rapid iteration model (ship early, learn from usage, adjust) works well for consumer services but works not as well for B2B services.
5. Hire people who are passionate about the specific problems you are trying to solve.
6. You must get close to your users and customers and live their personas.
7. The value of your company is directly related to your capital efficiency.
8. In the early days, I highly recommend that you force your startup to be resource constrained.
9. Don't listen to outsiders who tell you to go faster and ramp sales and marketing.
10. Avoid field sales in favor of telesales.
11. Once you are in the market and have established some measurable and repeatable levels of success, #11 negates #8 on this list.
12. Have fun.