Here are few very very important aspects of SEO which you should never ignore.

1. Content is the King
2. Content in images/flash/animation/vedio is not the content for search engines.
3. What is good for Visitors is mostly likely to be good for Search engines also.
4. No negative techniques will work.
5. No one can promise you No. 1 position for a keyword.
6. Aim for more relavant traffic from search engines and not rankings