Make some simple stuff in PHP and Mysql? That's what I did first time around, then I got really interested in the cool functions, and now here I am. I don't remember exactly how long I've been doing PHP code, but I think around a year and a half or so.

Examples of PHP and MySQL systems:
news
blogs
forums
gallery
membership
point system / rating system


and many more.

Or you could do what I also did and practice every single function every day. At least 3 functions at a time, and made many examples with them.

In your position, I'd bet recommend starting with a simple news system.

__________________
VillageIdiot can have my babbies ;d