In Chapter 6, we covered theme development pretty thoroughly, though you can get a much more in-depth tutorial in theme development from the excellent book "WordPress Theme Design", Packt Publishing, 9781847193094.
This section will clearly list the top template tags and stylesheet classes that you'll want to have if you're going to be developing themes. These are the most essential (with some of my personal favorites thrown in).
In the list that follows, I do not cover the arguments that can be passed along with these tags. You'll want to visit the Codex to find out about the default settings for each tag and how to override them.
The header and informational tags are as follows:
What it does