I am in the same phase, i have 1 idea which "I" think is good one but not sure if there is really need for that. So i am basically putting my efforts without keeping much expectations from it but giving my 100%. You have to try it to find out if its successful, idea may be great but implementation of it will decide the success. Keep on looking for inspirations, i came across site where they are selling tickets to marriages, i mean really? i visited the site and there were listing available.

So try it and find out yourself, worst case it wont be hit/successful but by that time you would have learned so many things.