2. Between now and then, work at a small company, a just-funded startup, a raw startup and a big company (maybe in that order, maybe in any order). Watch the management closely and LEARN.
3. No matter how frustrating it is to work for someone else, stick to your plan.
4. Keep your technical skills current.
5. Learn management skills.
6. Save your money - live frugally now so you can self-fund your startup and keep control of it.
7. Become an expert or become good friends with an expert in some domain - gaming, architecture, finance, whatever.
8. Do your startup in that domain.
9. Develop a healthy lifestyle. You'll need your all your health and stamina to make the startup succeed.
10. Regularly sell things on eBay and/or Craigslist to get used to selling to people.
11. Watch how your non-technical friends use computers. They compose most of your customer base.