2. The best way is to write certain articles and post them on other sites which include a link back to yours. Or ask other webmasters with similar sites to link to yours.
3. That's much better. Just any site with the content made clear and the ads in place, but not obstructing the users experience.
4. I have no idea what's wrong with your WordPress theme.
5. Yes. SEO has more facets than I can care to write about right now. All-In-One SEO is a great tool, but it only makes your on-site SEO optimized in the easiest way for you.
6. You can use programs you pay for, but the easiest for a beginner is Google's keyword search tool
7. I think putting a link to some good Amazon books in your sidebar would be great. Post reviews of them or something too.
8. I am not well versed enough on eBooks or Kindle sales to give you a qualified answer. I know about SEO and a decent idea of marketing/selling things online. I suggested an eBook because people buy them and you are apparently very knowledgeable in your field.