Have a go at making a simple blog. Doesn't need to have anything fancy such as pings/trackbacks just something simple that allows you to post entries and allows others to view them

When I was starting out I found that it held my concentration better if I could see the application in action as it progressed. For example, for the blog, I would just make the viewing part (with some test data), then make the posting part, then add on a little keyword system, then a rating system, then comments, etc.

It's much more fun to see it progress rather than have 3 pages of features and no idea where to start coding

Good luck!

Alan