One of the best tips I’ve ever read on writing is, when you start putting pen on paper, start somewhere in the middle…some part of the story in your head you’re attracted to the most. Don’t try to write from the very beginning. We spend so much time concerning ourselves with the big, attention-grabbing opener, when, in reality, it’s a rather insignificant portion of the entire story. There’s a considerable amount of work after the opening paragraph.
I’m pretty sure you can apply the same general concept to building software. After all, in many ways software has a beginning (logon), middle (do something), and end (leave). Instead of starting software at the beginning, start at the place you’re most comfortable or excited about.