your main problem was you lacked active counterplay, and therefor created no weaknesses.
Ater 9.na5 I wouldve played c5 putting pressure on whites centre and only then moved the knight back.
The structural weaknesses you gave up were the main problem.
After more or less completing your development you appear to drift without a clear plan. White has supremacy in the center so it would be good idea to try to engineer pawn break there with either c5 or, perhaps better still, e5. For example 13... e5 could be considered.
guys this isn't my game. Its my friends. I would like to know how to break the queens gambit on a normal basis. This match was an example that I picked. But normally if you were to play great in the queens gambit how would you play against it. BTW this is my match against another queens gambit guy. How would you destroy him?
what the two above me said you don't really have a clear objective your a tad more indecisive when it comes to playing against it.. I.E. if your oppenent plays Queens Gambit you can always play French Defense or Karo-Kahn but try being more agressive if your opponent plays it on another note i noted when you played 33. Kg2 Rb7 34. Rc6 Rb5 instead of Rb5 you should've played Rb8 or push your pawn on the H-file to H-6 or H-5 there isn't a clear win-win situation for queens its more along the lines who can capture the most pieces and have a better overall advantage. so if you had drawn that game out and avoided the checkmate what do you think you would've played in an attempt to even up the score and win that knight + pawn positioning
Also whenever i play Queens gambit i Start out with French and then i transition over to Sicilian then switch to Sicilian Dragon formation here i'll link you one of my games
Elite_Spartan, based on your orginal post, BOTH SIDES played the opening extremely weakly.
First off, for Black, 2...Nf6 is a horrible move. It's known as the Marshall Defense, and should never be played. Black should respond with either 2...e6, 2...c6, 2...dxc4, or if Black really knows all the theory, and is rated over 2000, maybe 2...Nc6, but that's a whole different game. White should literally punch Black in the mouth for playing 2...Nf6, and take on d5, and when Black takes back, if it's with the Queen, 3.Nc3 making her move again, if it's with the Knight, take over the center with 3.e4!
As for White, not only should he played 3.cxd5 after such a horrible move by Black, but he should also not play e3 before pulling the Bishop out to f4 or g5 (g5 being the more common choice). With correct play, assuming you are talking the Orthdox Queen's Gambit Declined, since you played e6 in your example, play should go as follows: 1.d4 d5 2.c4 e6 (NOT 2...Nf6 3.cxd5 with a clear advantage for White) 3.Nc3 (NOT 3.e3, if White does this, Black has an easy game as White's bad bishop is behind the pawns, putting no pressure on e5 and c7 via Bf4 or on the Knight on f6 [and in return, on d5 after the elimination of the Knight on f6] via Bg5) Nf6 4.Bg5 Be7 5.e3 Nbd7 6.Nf3 O-O 7.Rc1 c6 etc etc.
Can you help me exploit this guys weakness? I don't know what the weakness is. At the same time I don't know how to attack against him.