this is a tad old (and i am hopelessly behind), but i have to pass it on anyway: threadbanger met up with bonnie simmons of simplicity pattern company, who gives viewers (i.e., you and me!) a lesson on how to make croqius/fashion sketches (those oh so important precursors to making your own designs). she makes it look easy, eh? speaking from experience with this sort of thing (i drew such things until my hands nearly fell off whilst a student at parsons back in '05-'06!), practice makes perfect. not suggesting you have to pull all day long drawings sessions like i had to...but if you keep up at it, you can get fairly good. give it a try!
as a related aside, two books that i found invaluable on this subject of making fashion illustrations (should you be interested) are 9 heads by nancy riegelman, and fashion sketchbook by bina abling. any of you designers out there have any alternative suggestions for fashion drawing/illustrating tomes? chime in!