I have had websites attacked in a variety of ways — mostly unsuccessfully, thankfully — and I have heard of and seen even worse attacks on websites occur to others. Listed below will be some of my favorite security tips and tricks. Some may work on any website, others on more specific setups. Don’t worry, though, I’ll try to give you all the information you need to know.
Apache
If your website is being served by an Apache webserver (more than likely, it is, but check with your host to be sure), you can make use of these tricks to secure your site at the server level.
WordPress
If you are using WordPress, you can lock your site up tight with these tricks.