The most general rule of thumb states that it's best to allow your hair to naturally dry instead of using something such as a hair dryer. This is especially the case if you are wearing a weave that is either curly or wavy. Use a clean towel to pat your hair dry after you wash it. Afterward, you should let the rest of your hair dry naturally. If you absolutely need to use a hair dryer, use a medium setting to minimize heat exposure.
Never roughen your hair while you are drying it. Additionally, you should also never go to bed at night with hair that is still wet or damp, as this will increase the chances that it will be frizzy and/or tangled.
If you have curly or wavy hair, you should totally avoid hair dryers in general.