1500 Online - I learned lots

Here is a game I finished today. It ended in my winning because of some late-game blunders, but what made me decide to showcase it were a few of my moves which really pushed me to the limits of my ability, and hopefully beyond. Kudos to my opponent who really forced me to try to find the best move.

Like move 12, where I played the simple Ra7 after four hours searching for safe ways play Nc6, but only finding tactical refutations 10 to 14 ply deep. Or moves 15 and 20, simple pawn moves that restricted white's pieces, but are difficult for someone of my ability to find.

This game really helped me develop my analysis and evaluation skills. It also made me realize how much more room for improvement there is. After the queen exchange (move 25), I had no idea what strategy to follow in the endgame with rooks, pieces, and pawns still on the board. This is often considered "technique" even if the result I'm shooting for is a draw. I know the purpose is to exchange pieces and pawns with the goal of ending up in a won or drawn simpler endgame, but that's easier said than done, as you can see from some of the predicaments I was in. After the game I took a peek at Silman's Complete Endgame Book to see if he had any pointers on such technique, and there is no help there. Does that mean this phase is played just like the middle-game, except with a more active king? Any feedback on "early endgame technique" would be appreciated.