1300 game. Had no plan. Gave away the win? What themes can I work on?

You have various options once it is stopped. You were up a piece.
You could have used your knight via d6- c8 -a7 to win the a pawn and then get a queen.
You could have used the knight via d6 and b4 together with your other rook to win your opponent's d pawn.
If he moved his rook on f8 in order to be able to help his pawns, then his f and g pawns will fall with check. Together with your knight, there is probably a mate in there before he could get his pawn to queen.
It is a great thing to be up a piece. All you had to do was stop his c and d pawns. To stop pawns with rooks, you want to get behind them.
Ok, so I needed to be patient and realize Black was stuck in a "stalemate" and I could just grind off another piece and turn the tide.

@OP: Black was short of options, but the term "stalemate" does not apply. "Zugzwang" would be a more accurate description (but still not really applicable, because Black could have tried something). Stalemate is a specific type of drawn game. Therefore, stalemate is something that happens to both players in a game.
In your above game, Black was losing, and so of course could not have been in a stalemate as well.
You seem to have been undone by time pressure, which is a shame. But if you just remember "Rooks belong behind passed Pawns," you won't need to fall victim to this type of problem again. That adage applies to both ally and enemy passed Pawns, making it even more convenient to remember.
What would bringing my other rook to d7 accomplish? I would then just have rooks on C and D and stuck in a mutual zugzwang.

@OP: "Mutual zugzwang" refers to both players, White and Black, being in a situation that neither player wants to have the move. When one player has two pieces that can't move, those pieces are "tied down to defense."
With both your Rooks on c7 and d7, you would be winning, yet Black would have advantageous aspects (i.e., his passed Pawns). One question is, which units are stronger, your Rooks or Black's Pawns? The answer is, your Rooks. Though they couldn't move (much), they would be exerting powerful defense.
The key is your Knight, which is your material advantage. Your opponent didn't have one, so your Knight would have been the key to winning, picking off the weak Pawn on a7 and promoting your Pawn on a6. With your Rooks dominating the Pawns on the c- and d-files, Black would have been entirely helpless.
Yes, whirlwind, I needed to be ok with the "logjam" in the middle, and leverage my knight to slice off the advantage on the fringes. Deliberate patience grinder was the winning move in this game, which is the opposite of blitz play, which is always looking for the KNOCKOUT punch, which is how I failed here. Thanks!

I was really intersted in what happens after 16 bxa5. I think you where too. I was rather suprised I could not find the position in at Chesslabs. So I had to turn to Stockfish.
Which is a very long way of Saying. I think your instict was correct; I dont think taking the knight would have been good for White at all really.
As to your Original Question, If your going to continue to play 1.e4 e5 2.Bb4 ... I Think you might take some time to study some games in the line that go at least 41 moves. (A typical break point under the old Adjurnment rules.) Till you develop some feel for the end games that result for these positions; I expect it would help you plan better. Your comment at move 37 seems to me to indicate this might well help.

@OP: I notice that you have comparatively few Live Standard games and very few Daily (Online) Chess games in your completed statistics. If you play some more games in longer time controls, you might practice and explore the slower, more disciplined, positional side of the Game.
Ouch. We've all been there.
I'm sure you've gotten some good advice. I'd just point out the position after 25.a6 is applicable to a lot of other situations for two reasons.
1) The knight blocks the rooks. This sort of blunting can happen on diagonals or even a knight's path too. The pieces behind suffer, so ideally the piece in front is doing work.
Often players get the illusion that the piece in front IS doing good work. A knight on the 7th rank can be pretty great right? Here, not so much. It's hitting air.
2) Redundant pieces. The a6 pawn and both rooks all serve the same purpose. Sometimes you can look at each non-pawn in turn and examine the role you've given them. Often many pieces will be doing the same thing, which is sometimes good. Overprotection for example. Other times though it's unnecessary and you can improve some pieces by giving them different jobs.
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Which, by the way, is how you can force your opponent to trade pieces. Don't just offer a trade (your moves 26 and 28). Force the trade by making your pieces as active as possible. Putting your rooks on his 7th rank is a great example which (potentially) completely shut down his position. That's the sort of choice you want to give them. Trade, or let my active pieces tear you apart.

You are losing at move 9.
I prefer the move 8.h3 in this position.
The move 8.Nc3 is playable.
However, if you play 8.Nc3 you have to be able to handle the move 8...Bg4.
In your game you did not handle it correctly.
9.h3 gives black an advantage after the following moves:
I will not explain how to play the move 8.Nc3 correctly.
For more information on that you will have to read the below forum:
http://www.chess.com/forum/view/chess-openings/bad-bishop-problems
I honestly don't feel like rewriting everything I said on the other forum again to this forum.