1. Tell us what you’re trying to accomplish with your .htaccess file. URL redirects? Cross-domain access of fonts for Firefox? Setting MIME-types? What’s the goal?
2. Tell us what isn’t working, in detail. Are your redirects failing to take effect? Are your fonts not working? Are you getting any errors? Could it be a simple permissions issue (WordPress, for example, needs read-write permission on your .htaccess file to make any changes from within the dashboard)?
3. Paste the contents of your .htaccess file.
4. Where is your .htaccess file? Is it possible it’s in the wrong folder? It should probably be in the root directory of your site. On most hosts, this is /public_html, /www, or /var/www. If you’re running WordPress, it needs to be in the root folder of your WordPress installation.
5. Finally, if it is a redirect issue, check with your hosting provider to ensure that the Apache mod_rewrite module is enabled.