In Where Good Ideas Come From, Steven Johnson writes about expanding your possibilities simply by moving forward:

“Think of it as a house that magically expands with each door you open. You begin in a room with four doors, each leading to a new room that you haven’t visited yet. Those four rooms are the adjacent possible. But once you open one of those doors and stroll into that room, three new doors appear, each leading to a brand-new room that you couldn’t have reached from your original starting point.”

It reminds me of the second kind of luck that Marc Andreessen referenced in his blog, the luck that comes with motion—because: no one ever stumbles on something sitting down”:

“A certain [basic] level of action "stirs up the pot", brings in random ideas that will collide and stick together in fresh combinations, lets chance operate.

Motion yields a network of new experiences which, like a sieve, filter best when in constant up-and-down, side-to-side movement...”

If you’re looking for a career change, trying to get a startup idea going, starting a blog, really to just make anything happen you’ve simply got to start moving forward—even if you don’t know where it will take you or how to complete the project over the long term.  Short term milestones to keep you in check are important, but too often people sit on the sidelines waiting, when opportunity favors people in motion, because it enables them to see more cards turned over in the hand.