Regularly read Wikipedia articles on computer science, programming, logic, and perhaps mathematics and/or linguistics topics. Get Firebug and inspect the code of sites you like. Start building something with HTML, CSS, and JavaScript. Constantly improve what you're working on, and don't be afraid to ditch what you've got and start something new.
Focus on JavaScript. Watch the SICP lectures, read Doug Crockford, Raganwald, John Resig, and pg's Arc source. Learn the ins and outs of emacs, vim, TextMate, or Eclipse. Play with Lisp, Python, Ruby, and Io and read others' code in those languages, then apply what you like to your style of writing JavaScript. Try out the major JS frameworks (jQuery, Prototype, MochiKit) and settle on one of them. Then rig up a server-side JavaScript solution (Jaxer, Helma). Pick an interesting domain and learn about it until you find an overlooked problem you can solve, then capitalize on it.
Focus on JavaScript. Watch the SICP lectures, read Doug Crockford, Raganwald, John Resig, and pg's Arc source. Learn the ins and outs of emacs, vim, TextMate, or Eclipse. Play with Lisp, Python, Ruby, and Io and read others' code in those languages, then apply what you like to your style of writing JavaScript. Try out the major JS frameworks (jQuery, Prototype, MochiKit) and settle on one of them. Then rig up a server-side JavaScript solution (Jaxer, Helma). Pick an interesting domain and learn about it until you find an overlooked problem you can solve, then capitalize on it.