For most pages, two sizes will be enough. Pick a large and a small heading and use them consistently. Your logo, graphics, and navigation buttons already add a lot of variety. Varying the size and type in your text is a better way to help readers identify the relative importance of ideas presented. Use a different font when you want certain material visually set off from all the rest.
Colors Use colored text sparingly and consistently.
Links and used links already put two colors on your page. One or two other colors can be used for emphasis, or visual punctuation, but more is NOT better . Use background colors even more cautiously. Backgrounds You can set background colors for entire pages. If you use tables, you can add color to portions of pages.