I second all the suggestions of @statictype. Find various ways to receive unbiased opinions from ppl who fit your target user group. Don't invest too much time

I second all the suggestions of @statictype. Find various ways to receive unbiased opinions from ppl who fit your target user group. Don't invest too much time UNTIL you've received enough validation. As a compliment to that, I highly recommend that you read The Lean Startup by Eric Ries. Best of luck.