The job of search engine optimization is to optimize your site, making your site search engine friendly, easily indexed by search engine and shown in high positions. Internal optimization, or called on-site optimization, includes keyword definition, meta tag generation, content writing, and the creation of robot.txt file. External optimization, or named as off-site optimization, is link exchange.
The principle behind these jobs is that major search engine use content relevance and link popularity as the key factors to rank your site. Other factors (maybe hundreds) include link title, domain name, etc. Of course, you are not able to work on each deciding factor. We suggest that you focus on the two factors first.
