Some tips for your wordpress blog before you can optimise for search:

header tags

• make sure you have the proper header tags in your pages
• dont make the title of your blog be an h1 tag
• only have one h1 tag per page
• make sure the h1 tag is on the title of your blog post

w3c code validation

• make sure your html code validates from the w3c validator
• make sure your css validates from the w3c validator
• make sure your rss feeds validat from the w3c validator

images, urls

• make sure all your images have alt tags
• make sure your anchor (links) have a title attribute
• make sure  your urls are properly formatted (set your permalinks to have the title in them)

meta tags / sitemap

• make sure you have meta description and content tags for all pages (use all in one SEO plugin or gregs high performance seo plugin)
• make sure you have a sitemap and that its submitted to the search engines

once you have done these basic things, then you need to check your inbound links, and make sure none of them are causing 404 errors, if they are then 301 them to the correct place

make sure your content is readable by humans too. and make sure your theme is readable by humans!!

you should now have a decent platform to actually start optimising for searches.

I just ran my site through the nibbler free test, and managed to get 8.0 – thats pretty good, since my inbound links are just about non-existant. it means that im in a strong position to start with. as should you. search for nibbler and test your site, and see what it says.