I use XAMPP as a local test server on my Mac for testing and debugging. I mean, nothing is more embarrassing than making file changes to a live site and bringing it down. One thing always bothered me, but not to the point of solving it. WordPress, Drupal, and other CMS software provide built in automatic updates or installation - but out of the box it does not work on XAMPP. It's a simple fix, just first hunt down your httpd.conf If you need help finding the httpd.c0nf, take a peak at /Applications/XAMPP/xamppfiles/etc/, and the file is located there.
Watching file sizes and following coding standards are only one simple way to optimize your website. Proper HTML will ensure you page is processed as smoothly as possible, but does not mean a major speed boost. When the dust settles from developing a new website, I turn to Google's PageSpeed for the round up of last minute tweaks.
The easiest way to learn PHP is to be able to create and edit code and see instant results. When I was younger and learning I couldn't afford to have my own web server so I installed a WAMP environment - I also didn't have a spare machine laying around to toss Linux on. Unfortunately I never heard of EasyPHP until a bit ago, it was originally released in 1999, but you can Wikipedia that. What EasyPHP does it streamline the process of setting up Apache, MySQL, and PHP and installs phpMyAdmin along with other modules if you choose.