Perhaps play 20... Nd3. This attacks the bishop and the b2 pawn. He would likely play 21. Bd4. After that perhaps Rxb2 instead of Nxb2 is better because it forces white to respond to prevent a backrank mate and you can keep the initiative.
Maybe instead of 15... Rb8 you could have played 15... Rd8 that way after the bishop develops you still control that square and have a strong D-file.
At the end of the game I think it was essentially drawn as far as the position goes and with accurate play from both sides it would have resulted in a draw ultimately.
Still a good game. I can't be of much assistance for the opening because Petrov's is not one of my openings. As white I play to get out of book as quickly as possible.
I recently played a game against a higher-rated opponant and managed to gain what seemed like a slight advantage into the endgame, but I managed to give it away and let him force a draw.
Any insight on how I could have formed a better plan would be appreciated. Advice on the game as a whole would be helpful, but it's this endgame I'm most unsure about. Thanks a bunch.