Firstly, make sure your code is valid. This involves using a Doctype declaration in the main html. Send the whole site through the W3C validator, the errors are verbose enough to be useful to make good changes.
Also, I would suggest separating out your CSS an JS from your HTML and rather reference them. This makes the raw code easier to read and maintain and, believe it or not, can actually solve some of the inconsistencies.
After all of these changes, then you can start making fixes for IE. The Google IE7 JS is pretty good, but I would hesitate using JS to fix what proper conditionals and good CSS can fix.
I would also suggest having an arsenal of web browsers to test in. Even if you don't use them for browsing, testing with them is crucial. I suggest IE6 and IE7, Firefox, WebKit (or Safari), and Opera. I've had completely valid sites fail in Firefox, while be fine in all other browsers including IE.
At least browsers are getting better
Oh, and here is a great site to brush up your skills:
http://www.alistapart.com