I've found the YC Build Sprint to be a fantastic driver of focus!
I set what I saw as modest goals at the beginning:
(1) sign up at least 25 beta users,
(2) add at least one new social media network to the app based upon beta user feedback,
(3) get app store approval and launch!
1 — 10 users signed up
2 — this ain't gonna happen
3 — achieved, but a week later than hoped
I've learned quickly that, at Xapnik's stage, just getting 25 users in three weeks (we lost a week to the app store rejection) is plenty to focus on.
We're quickly learning which parts of the user experience so far are confusing, broken or below expectations.
Today, I'm 'pounding the pavement' to get as many of those 25 (targeted) users signed up. If I can exceed that goal by the end of the sprint and come away with the punchlist of priority changes to make for the next release, that'll be more valuable than shipping goal (2).