Most blogs that I see are not remotely spider friendly. By that I mean the search engine spiders have to wade through a good bit of html only to find there isn't much there but the posts. Each and every blogger has to view their blog the way the spiders do, and then fine-tune things to be not only spider friendly, but also to spoon-feed the spiders what you want them to eat. How do we do that? Well, for starters use a utility that examines your blog the way a spider does.
There are several simulators available that will do the hard work for you. They visit your URL, strip out the HTML code, and serve up the meat of your blog site the way a spider sees your site. Here are the best sites to use:
WebConfs Spider Simulator
SEOChat Spider Simulator
Webmaster Toolkit Spider Simulator
Fix Your Theme
Now that you have looked at your site using one of the simulators, you may notice that there are no meta names or descriptions listed. You may even find that the top lines are spam for your theme designer. The first thing you need to do is realize that most themes are designed for looks, not for search engines. You need to add some "meat" to your theme by way of meta descriptions and keywords. In WordPress, you will probably need to open your theme editor and use the header.php which is where most theme writers put meta information. Examine what you see closely. With Blogger, you will need to use Blogger's theme editor for the main page. For starters, try adding a line in the section of your theme for keywords. Although Google does not put much emphasis on keywords, some search engines do. A meta keyword listing would be something like [meta content="term1, term2, phrase one and two, another phrase, term3" name="keywords" /] (we used square brackets so this code will display. Replace with angle brackets).
The terms and phrases, obviously, should be something relevant to your site that you would like the search engines to pick up. Try running a simulator again and see whether the keywords are now being picked up. With the WebConfs spider simlulator you not only get the meta listing, you also get links from each of your keywords to other suggested keywords. Experiment, learn about meta and how spiders looks at your site. Fine-tune your site. You may have information in a sidebar that is being wasted. Notice where the spiders put sidebar information. Keep in mind that most spiders consider text at the top of a page to be more important than text near the bottom.