The move 15...Be7 was not the best. Stronger was 15...Be5 to control the long diagonal and pin the knight, then attacking his kingside with ...h5 and ...h4. 18...Bf6? is bad, but White misses the strong 19.e4 Ne7 20.Nf4 and 21.Bxf6. Instead of 18...Bf6, best may be 18...f5 and if 19.Nf4, then 19...Qf7 is ok for Black. Instead of 19...Qxf6, better may be 19...Nf6, and if 20.Nf4, then 20...Qe5 should be ok for Black. After 19...Qxf6, White had a better move with 20.e4 Ne7 21.Rxd8 Rxd8 22.Rd1 for control of the center. After 23.Qxd4, it is no good to trade queens (you lose the endgame and he controls the open file and gets to your 7th rank with the rook). Keep your queen on the board for possible counterplay and try 23...Qe6 or 23...Qf5. Instead of 27...Rf7, you might try to stay on the first rank with your rook (27...Re8 for example) and try to play 28...Nf8 and 29...Kf7 and get you king active in the endgame. Instead of 28...Ne7, try 28...Re7 and 29...Kf7 and make room for your king to advance. It is important to centralize your king in the endgame as it is another fighting and defending piece. 30...f5 looks weak. Still the idea of 30...Re7 and 31...Kf7. After 30...f5, White missed the strong move of 31.e5 with a passed pawn. After 31.h5, the knight should have gone to 31...Nf8 (32.Rd8 fxe4 can be played), aiming for ...Ne6. Now White controls the 7th and wins a pawn. 33...fxe4?? and it is over. Best you can hope for is 33...Rf7 34.Rxc7 fxe4 35.Rxb7 Nf5 36.Rxf7 Kxf7 and 37...Ke6-Kd5.
Where am I going most wrong
11...Bh3 moves the same piece twice in the opening, before you've developed your rooks. That's by far the most common mistake I see in most games posted here--moving the same unit twice in the opening--and I even predicted before I went through this game that's what I would find.
9...Bg4 doesn't do anything useful and is just asking for White to drive away that bishop and cause you to lose a tempo.
10...Qd7 is just asking White to drive away your queen with Rd1 and cause you to lose a tempo.
13...Bd6 is just asking White to drive away your bishop with c5 and cause you to lose a tempo.
28...Ne7 is just asking White to play e4 to prevent that knight from going to its only two potentially useful squares.
Yes, I'm seeing a pattern here: You're putting pieces will they will be driven off, or where their destination squares will be taken away, all with simple moves from your opponent that gain space while you retreat.
I believe I would have played 19...Nxf6 instead of 19...Qxf6. That's where the knight came from, it has no future at d5, and notice how your pieces started getting in each other's way after that: queen blocked from the protective e7-square, knight misplaced at g6, etc.
Personally I think 5) Be7 is a waste of a tempo. It doesn't really develop anything. I don't think you needed to be worried about activating his queen. You didn't have any obvious positional targets. Also queens tend to cost white a tempo that early in the game because she can't often be traded. I think you were right early on with your assessment that you should have traded knights. I also think that at move 6 you castled to early. To me the position isn't clear enough to decide where to castle. You essentially made your king a target with such a commital move. Now white knows where to coordinate his attack. Also 9) bg4 to me is a wasted move. It doesn't attack anything and can easily be refuted. To me the biggest fight in this position at the moment was for the e file. If I were you I would have been looking for a more potent square for my light colored bishop and then moving my queen to connect my rooks and then fighting for the e file which came back to bite you later. To me 9) be6 is better because his c pawn on c5 is hanging and is a target. So white now is forced to waste a tempo to defend it meanwhile all you have left is a queen move to connect your rooks and then you can really clamp down on the e file. I feel like you were reacting to white all game because he started with an opening you didn't recognize. Also when he played a3 you had to see b5 coming meaning you were going to lose a tempo against the bishop and losing space as well. Why not move it as soon as you saw a3. On top of which if you were going to trade your light colored bishop why not do it immediately instead of doing it only after a3? I agree his light squared bishop was slightly better than yours but still another wasted tempo. Although I might have kept my light squared bishop because he was an important attacker of the black king especially since black fianchettoed his bishop. I might have played for a way to trade a kinght for black's light colored bishop. This plan would have worked better if you castled queenside and did a pawn storm toward that king. Not sure how sound it would have been just throwing ideas out. Im an attacking player as you probably can tell. Anyway you are a better player than me by rating so what do I know? At 20) why move the knight back? It was controlling a lot of central squares in that position and was your strongest piece. I would have been looking to neutralize the e4 pawn push that was sure to come but I wouldn't have went back unless forced to. at 21) rad1 why not trade on d4 immediately and then plop that knight back onto d5? Knight g6 is just so passive and out of the action for the efile. 24) f6 was the right idea wrong move order. I would have played knight e5 then f6. It protects d7 then I would have got my king into the action to help defend d7 with moves like king f7 etc. Not saying you would have won, I definitely prefer white here especially with your doubled c pawns but still you could have played for a draw. Just my two cents. Hope it helps.
Thanks for the comments, all of which I have played through. The game illustrates q few of my weaknesses. I have a reluctance to push pawns, preferring to hit on the counter, but in cases like this I can find myself out of room in the endgame and often at other times I am behind in the queening race. In positional games I can be passive, such as here, retreated the bishop to e7 instead of e5 where it will be met with Bb2, losing a tempo to exchange the light bishops, and (MSanders) taking the knight off d5 (from which it could anyway be kicked) with the vague idea of somehow getting it to f3 via g6 & e5. Finally, another of my foibles ends the game when I spend time analysing a candidate move that is no good and then play a different move quickly (even one I had rejected earlier, as here) and blunder. Thanks again for all the feedback.
Be7 then Bc5? Seems like just a waste of time in the opening. If you're going to play Be7 then you should follow it up with something flexible, like Bf8
Did you consider 5. ... Bb4? It pretty well commits you to exchanging it if challenged, but it neutralizes some of White's central build-up (e2-e4 becomes much more difficult) and makes your f6-Knight more relevant.
This game ended with a blunder - until then I felt I played ok but gradually was ground out. I'm wondering where I should have played differently to avoid the problems at the end where I had no space to manouvre.