You can read through this tutorial from beginning to end and pick up a wide variety of tips and advice on how to improve your PHP code without having anything in particular installed.

For the most value, you may want to construct and run some of your own test cases. To do this, you will need a working installation of PHP on your machine. You should probably have the following:

• Any OS supported by PHP (http://www.php.net/manual/en/installation.php).
• PHP (http://www.php.net/)
• A Web server under which you run PHP is optional. Alternatively, you can run PHP from the command line.