Some sites use style sheets that are included in the header of each web page. If can be a good idea to find a style sheet on a page you like and adapt it to your own use. As well as informative titles and helpful navigation which appears early on in the page, this involves using link text that is informative about what the link is to. If you have used tables and alt text carefully, the site should still make sense. Otherwise the content will appear in a funny order and links will appear without any indication of what they link to.
Lynx is a text-only browser available from the command line of many university servers.
Read aloud what you see on the screen. A free online tool that I highly recommend is Bobby . It automatically checks your page and warns you about aspects that may present a problem for disabled users. Because it is just a program, it is only provides the most basic check. It cannot verify that your headings are helpfully written, for example.