You've just asked one of the biggest web development questions there currently is out there.
Designing for accessibility compliance is a vast topic, and not one to be easily broken down into a simple 'if you A, B, C then all will be as it should be' scenario.
First port of call should be the W3C site click here which contains more information than you probably want to know about accessibility issues.
A more appropriate (in your case) series of links are click here click here click here - this assumes that you are still using FrontPage of course. If you aren't perhaps you could indicate the software you will probably be using since it could make a difference to how best to proceed.
You will see from the content in the above links that FrontPage has some interesting tools to assist in developing accessible pages and sites, from ALT tags for images to DOCTYPE headers and more.
Spend some time reading the content I've given you the links for, and next time you're in FrontPage hit the F1 key or click on Help and type in the word accessibility to the help content search. you will get tons of built in explanations, hints and so on already built into the FrontPage help files.
Hope that helps a bit.