Linux, with Apache? nginx? lighttpd? There are different rewrite methodologies for each.

Have you installed the module and activated it? You will need to be on a private server of some sort to do this, most shared hosts will not give you the option (if you are on shared, ask them about their policies)

Have you double checked all the information provided above? Some of the simplest things can be overlooked and completely default the other attempts you've made.

Have you double checked your mod_rewrite rules that you are attempting to use? Start with something basic, such as removing file extensions or just accessing a single page from a slightly different name.