Kinda tough. You don't need a lot of equipment... just a basic computer with Cakewalk, a small mixer, a mic, a guitar and maybe a couple of effects and you've pretty much got a complete studio. Most decent audio recording software can record at least 24 tracks or more and a lot of them also include things like drum machines and VST synths. Once you've got the recording stuff in place you can start experimenting. If you've got endless tracks to work with, just record 50 different tracks of random stuff over top of your song. Then try splicing different parts together.
If you can, get guitar loop CD's specifically made for this purpose.

I suggest getting into recording cause pretty much every band I've ever been in has written songs that way. Somebody brings in an idea on tape. We fool around with it and record the rehearsal. The writers take a copy of that tape home and use a multitrack to add other stuff to it then everybody gets a copy of the final tape to learn the song from so you don't have to rehearse all the time. Eventually we'd go into a high end studio and refine it even more. Nowadays though, all you need is a computer with Cubase or whatever.

There's all kindsa kewl tricks you can do these days. Like, if you can't figure out a guitar riff for a song you've written, record the song and convert it to MP3. Then use software called 'Amazing Slow-Downer' to bring it down to half speed. Play that and record a solo an octave lower than you normally would into some audio software, then double the speed back up to normal. You might end up sounding like Malmsteen in some places but you end up coming up with all kinds of new ideas when you aren't limited by your playing speed.