Nothing throws off a screen reader more than non-standard, incomplete or incorrect HTML tags. Organize your pages well . Where possible, break up long lists into smaller sublists, with appropriate labels or headings. For example, if you color code certain words with CSS, the colors will be lost in text-only browsers or screen readers. Links should be descriptive of their destination.
Many screen readers allow the user to listen to the links out of context.
Preview in various browsers , including old versions and a text only browser, such as Lynx to ensure that your pages are still intelligible. Tables with tabular data should be well-organized and summarized for clarity. Provide captioning and transcripts of audio, and descriptions of video. Use client-side MAP, and provide ALT tags for links. Provide alternative content in case the features are inaccessible or unsupported.