Here are some steps you should take to optimize your WordPress blog for search engines:

1. Change the Permalink Structure: By default, the Permalink structure in WordPress is very dirty, with url’s being shown as ?p123 etc. You can easily change this by going to the permalinks tab of the WordPress settings, and using a custom structure like /%postname%/

2. Optimize your Meta Tags: Write unique title tags for every page, and also write meta description tags for every page. You can use the all in one seo pack to make your life easier.

3. Use only excerpts of your post on the home page, category page and tag pages. This should help you to avoid facing duplicate content issues

4. Use the Xml Sitemaps plugin to generate a sitemap. The plugins default settings are fine. Simply upload and activate the plugin and you’re fine. But one other thing I do is to submit the sitemap to Google.

5. Use Proper Internal Linking Structure: It is very important to maintain a good linking structure within your blog. It helps keep visitors on your blog and helps in improving search engine rankings. Here are some steps you can take to improve your internal linking structure:

6. Optimize your Images: some of the ways you can do this in are – Use keywords in the alt attribute. – Include keywords in the image names – Enter a description in the title tag. – Use the Seo Friendly Images Plugin

7. Ping Sites after publishing new posts. Go to the Writing Tab and scroll down to the update services box. Add a list of sites you want to ping when you publish new posts in the box.

8. make sure your code is valid. Use the W3C Validator to check the same.

9.

make sure that your blog title is an h1 on the home page and that your post titles are an h1 on the post pages.

10. Choose between www and non www version of your site and redirect one to the other. You can use the Redirection Plugin for this. Another plugin which you can use is the enforce www preference. I redirect the non www to the www, but you can do whatever you want, it doesn’t really matter. Also, you might want to redirect the index.php version of your site to the homepage.

11. Lastly, use a related posts plugin, and use simple text based navigation. Also, optimize your anchor text when you link to other pages.

For A list of the best WordPress plugins, check out this post on Best WordPress Plugins. Another post you might like is this roundup of the Best Web Layouts