I find a good project to learn everything, is obviously to have a project which involves everything you want to learn. Try this:
I want an admin panel where I can put my own private tools e.g.
- Notes page (Textarea I can type notes into and save for later editing/viewing)
- A page to add user/admin logins for the panel (Ability to create a user that can login to the panel, also be able to remove and/or change the user details)
With the login page I would like for it to login using an jQuery AJAX Post function.
This is very simple but it should teach you the basic of jQuery/PHP/MySQL/HTML and CSS. And will cover topics such as sessions, database and user security etc...