Strangely enough, I also had a Q+2P vs. Q+P ending recently. (In which I was the winner.) 
I didn't know its theory, yet always found a plan:
http://www.chess.com/echess/game.html?id=20175284

(The queen ending is from move 26 on. I erred with 31..Qb2, instead of ..Qe6, but apart from that, I liked the positions.)

I was taught that in queen endings a supported passed pawn can easily be decisive, even if you are pawn(s) down. For a queen is very strong, she can give the most effective support. (If you can't keep the perpetual, you are dead.)

In my queen ending, I think it was crucial that my queen managed to occupy a central position early, thus defending key squares, both supporting the passed pawn and defending against checks. (I felt if I could make one move freely and defend against a check on the second, and so on, then I was improving.)
Since my king missed a healthy pawn shelter, there came a time when I felt I needed to get his majesty closer to the passed pawn, which my queen had to support from the neighborhood anyway, in order to avoid perpetual checks in the loneliness, at the edge of the board.

IMHO White helped Black a lot by allowing his better king shelter to be destroyed by h5-h4xg3, which meant, among other things, that the number of checks from the opponent I had to watch for had decreased, since I could now defend against some with counter-checks resulting in the exchange of the queens, which would decide the game on the spot, thanks to the passed pawn. 
I wonder how more difficult it would have been for me with a healthy pawn shelter for his king. What do you think?

Could you show us your queen ending?

What is the general evaluation of queen and pawn ending? I recently lost a game where I had Q+P and my opponent had Q+2P. I could not save the game........are these ending loss generally. What is the good source to study these endings ?