Could I have won somewhere here?
I saw several things that might have been improved to give you better chances of winning in general:
I would have played 11. Qd2 instead of 11. Qb3. The latter doesn't have any long-term threat, but the former does: Bh6, threatening to remove Black's defending fianchettoed bishop.
13. Qxd7 doesn't do anything except help Black develop after you lost two tempi to help him do that. 13. a5 would have been more consistent, even if not very promising.
14. Bd1 moves the same piece twice in the opening before you've castled or completely developed, and I don't see that its new location contains any significant threats. With 15...Nc5 Black takes advantage of the lost tempo since you can't defend your e-pawn and d3-square in a single move, which forces you to trade off one of your advantages--your bishop pair.
It seems to me that 20. b3 would have given you long-term pressure on Black's c7-pawn since he can't defend it easily and you have two nice piece outposts down there. After the next move the game suddenly becomes drawish with opposite colored bishops in a largely locked up pawn structure.
Rather than 27. Kf2 I might have started putting my queenside pawns on light squares to keep them out of touch of Black's dark-squared bishop.
Doesn't 33. Rc8 win a pawn?
One sneeky endgame strategy might have been to walk your king over to Black's b6-pawn, which would have been hard to defend. Possibly your LSB could have protected your kingside pawns in the mean time, if you hadn't put them on dark squares via 28. g3 and 36. f4.
Why don't you put this into an engine and find out the answer to your question?
The endgame looked like it was drawish. 11.Qb3 misplaces the queen - a typical move when you're not sure what to do in a position.
I would have played h4, with obvious intentions, with a much more dynamic game and chances to win.
At the 1800 level, oftentimes you'll actually to do something, instead of waiting for your opponent to blunder. You need some pressure.
5.h3 might have been an idea. That way he can't exchange a pair of minor pieces and thus relieve his space issues, and ...Ng4 is stopped to harass a Bishop on e3.
What about replacing 22. a3 with 22. b3 to set up a nice pawn chain? It stops the black bishop snaffling pawns in moves 29. and 30. Then again, it limits the movement of your bishop while his bishop can whiz down the diagonals. So what do I know?
#2 (see #4): The downside of 33. Rc8 Bd8 is the white rook gets trapped (Kd7) and there is just enough room for the black rook to get to a stronger place.
I offer pointers of style but that is somewhat subjective.
For example I would not have played 4. c4 as I would be playing Bc4, Be3 and keeping my options open about which side to castle.
At 14. I would have played b4 to dispute a major knight outpost.
By move 17. Black has the play, with the feel of a KID, where black gets plain nasty on the c1-h6 diagonal with bishop and knight.
On moved 20. Black's rook capture looked dumb to me just not quite dumb enough to lose.
Bishops of opposite are great if you can mount an attack ( Knight or Queen because they can change colour square control ) otherwise they tend towards a draw.