I played this game when I was solid in the 1600 range and wanted to see if I had what it takes to be a 1700. I didn't, and I would like to know what exactly was lacking in my game, because I can't help feeling there was a victory somewhere in here.

Hello,

 There was nothing to worry about with 3e3, it looks more like lack of opening knowledge than anything else.  5...Nc6 was first slight mistake maybe, because want to have pawn break c5 later. So 5..Bd6 , followed by castling looks better. Also, when finished development, chould think about exchanging bad bishop, which your opponent has helpfully made available. 7...Ne4 is helping the opponent exchange badly placed Nc3, 7.0.0 looks ok. 14 ...Bb4 and getting your peice trapped was horrible. Again just castling would of solved immediate tactical problems, you are still worse because of bad pawn structure. 

Do you really mean 18axb4 was a mistake by white? He gets 2R + B v Q. Afraid think was dreaming if thought was ever winning game.

         On the plus side, don't think you are too far behind opponent. Just basic development, not leaving king floating about in centre for no reason, and keeping option of pawn breaks would have given this opponent something to think about.

 

10 nxe4 and forking bishop seems easier for white then he can endgame with bishop pair

You seemed to give up at 20...cxd4, you opened the game to give white the centre and full mobility while leaving your queen trapped on one side of the board. Then you pointlessly pushed the h pawn with little plan until it was too late.

 I can see minor improvements in the opening and middlegame (especially that blunder 17... a5. But that mostly stemmed from 15..c5. If nothing else learn that lesson about blocking your own bishops rereat with a pawn when a pawn can shift you so easily) but I'd mostly advocate focusing on your endgame. 24...Kd7 would have bought some time for the kingside advance but it was a dead end anyway.

I think you might be trying to win games in the opening and middlegame and not focusing on your endgame. Be a little more bloody minded about retiring early.