The SEO and spam king at Google, Matt Cutts, gave a good talk on optimizing your WordPress blog for the search engines (especially Google) - he was speaking at the two day WordCamp 2007 conference.
Here the best tips to get your blog rank higher in search engines without buying or exchanging links.
1. Google doesn’t care about link depth (i.e. the number of slashes in your permalink won’t matter)
2. The file extension doesn’t matter - you could call files as php, html or even mattcutts.. this is not taken into consideration while calculating the rankings but don’t use the .exe extension.
3. Use a 3-4 word long ALT tag description with every image - good for SEO plus screen readers.
4. Use dashes to separate words, hyphens are OK but spaces are bad.
5. Standardize backlinks (don’t mix and match www with non-www).
6. Make sure post creation dates are easy to find.
7. Use full-text RSS feeds to get loyal users. partial feeds get more page views, but not as much love.
8. Don’t include the post date in your URL.