Hi there Rowan, best step for any new writer breaking in is to write and put stuff online - if you've the budget to do it, pay artists to draw one page strips and stick 'em online and let as many people know about them as possible. This does a few things - it gives you practice in writing and finishing stories (and having an audience read 'em) lets you see how different artists will interpret your scripts (so you'll learn to write comics for artists) and extends your (horrible expression) network - the artists you work with are all liklely looking for work too, and at some point they may break in to comics (many of the people I worked with in small press went on to bigger and better things - Al Ewing, Si Spurrier, Kieran Gillan)
Apologies for the delay - it's a small group and I'm still trying to figure out the best way to extend it and make sure it's useful!