I thought you played the opening quite well (I know very little of Queen pawn openings).
Surely you must know some as black at least?? Otherwise, hypothetically, when I play 1.d4, you're going to be in a spot of bother.
Yes, of course I know "some", that's why I wrote "very little".
I never reply 1. .... d5 to 1. d4 so I'm very quickly out of my book knowledge.
If you are playing e6, g6, c5, Nf6 or f5 - you are well inside my book. It seems to me that d4 is played at all levels extremely often not having strong book knowledge of at least a few of the openings (e.g QGD, King's Indian, Gruenfeld, Benoni, Old Benoni) would be a serious weakness. My opening knowledge is hardly perfect (I dodge nearly all Sicilian lines being the main weakness - usually play Alapin's or O'Kelly's variations - the Najdorf and Dragon have me running for cover) but I get greeted by 1.d4 so often, I would feel naked without an extensive armoury against it.
I can understand your desire to master the openings, would be lovely. However, I've played for many years (more than 25) at, above or slightly below the 2000 mark and my opening knowledge is perfunctory (to say the most). I have exactly one way of meeting all the major tries:
White: 1. e4
if 1. .... e5 then King's Gambit
if 1. .... c5 then anti Sicilan line : Nf3 Nc6 Bb5
if 1. .... e6 or c6 or d5 I try to transpose to the Blackmar Diemer Gambit
Anything else, I make up as I go along.
Black:
1. e4 then 1.... c5 aiming for Najdorf
1.d4 then 1. .... Nf6 aiming for a Modern Benoni
Anything else, I make up as I go along.
I believe that far too much emphasis is placed upon opening study at sub-master level.
I actually thought that for much of the game your control of the center was solid. Your opponent didn't seem to do much to advance his position. However, I think at 16.b4 you opened yourself up quite a bit for little gain, as already stated by The_Hess. That move allowed your opponent to develop his rook momentarily, and you lost tempo to counter it with 2 separate moves by your bishop.
The issue I notice is that you play moves that are tactical, and do gain you material, but you don't seem to pay attention to positioning, particularly to set up the ultimate goal of a checkmate. For instance, 20. Qb3 doesn't really improve your position for achieving checkmate, and it is such a defensive move, and really un-develops your Queen.
Start thinking more strategically. The best chess advice I ever received was before each move to ask "Why?" Why are you moving there? Do you get any benefit from the move, whether it is position, a pin, or maybe to set up an attack. Always why? I hope I was helpful.
(As a side-note...I am relatively new to playing chess myself, even though I have read quite a bit. So please take my advice with a large grain of salt.)