Outside analysis

The resignation may have been a bit premture, but other than that, I can't find other errors in this game

First, there's nothing premature about the resignation. Being down as much material as you are is probably enough to resign, but it's also forced mate.

25. ... Kh8 (Kf8 Nxh7#) 26. Ndf2+ Kg8 27. Nh6+ Kh8 28. Qg8+ Rxg8 29. Nhf2+ Qxf2 30. Nxf2# (26. ... Qxf2 27. Nxf2+ Kg8 28. Nh6+ etc.) 

"I can't find other errors in this game"

I'm sure we can help.

21. ... Ba4. Doesn't this just lose a bishop for no reason?

Alright, now that we're sure we can find at least one error in the game, let's start from the beginning.

 7. ... Bd7. Do you have a plan here to develop all your pieces? This gets in the way of the most natural way to develop your knight.

10. ... c5 11. dxc5 Na6. This seems to just lose a pawn while allowing white to give you doubled rook pawns.  

Notice how at move 16 your opponent patrols the center with his rooks while your rooks do nothing.  Perhaps 8. ... Qb6 would have been better so that the queen doesn't interfere with the rooks later.

17. ... dxc4 allows white's knight a free path to d6. 17. ... Bc6 puts up more resistance, though white already has a significant advantage.

19. ... Qc6 allows white to fork the queen and pawn on f7. 

21. ... Ba4 the idea was to misplace the queen from defending b2 so I could play Rxb2. I see now this was unnecesary.

7. ... Bd7 I had a choice between obstructing the knight or the d pawn. I chose knight

10. ...  c5 I thought he would not take the pawn to avoid doubled pawns. When he did, I revised my original Nc6 plan in order to recapture the pawn.

8. ... Qb6 didn't seem like a good idea before c5

17. ... dxc4 I played wanting to avoid risking my bishop. I was at that point planing to open the board and use the B vs N advantage to win

 19. Qc6 was meant to support the bishop against the knight and later when I moved him to attack d1

"7. ... Bd7 I had a choice between obstructing the knight or the d pawn. I chose knight"

7. ... Bg4 was also an option.

"10. ...  c5 I thought he would not take the pawn to avoid doubled pawns."

You have to consider all of your opponent's moves, especially the best ones! Doubled pawns can be bad, but not as bad as losing material. 

"17. ... dxc4 I played wanting to avoid risking my bishop."

How does 17. ... Bc6 risk your bishop? In order to make the bishop vs. knight advantage work, you must take away advanced outposts for knights. The pawn on d5 was keeping the knight from going to e4 and d6. On d6, the knight is more powerful than your  bishops.

7. ... Bg4 I did not like because it gives white the ability to trade material for position and brake up my castle.

On 17. ... Bxc6 white would have 18.Nxc6. Because of his earlier trade of a bishop for knight, I didn't think he will hesitate to trade a knight for bishop. 

I'm not justifying myself, I know I played badly. If nothing else, the fact that I lost should demostrate that to me.  I'm only telling you what I was thinking when I made the moves. Finding flaws in my tactics is far more important to me then finding mistakes in the current game. Don't you agree?

"7. ... Bg4 I did not like because it gives white the ability to trade material for position and brake up my castle."

I don't know what you mean. Care to give the moves you were afraid of from white? What would white do in response to Bg4 that would "break up your castle" or trade material for position?

"On 17. ... Bxc6 white would have 18.Nxc6."

You must be confusing 17. ... Bc6 with 17. ... Bxc4. Notice that I suggested Bc6, not Bxc4.

7. ... Bg4 8.Bxg4 fxg4 allowing a potential pin on my bishop

ok... Loomis and others pretty much covered everything so...

r u playing to improve Kingfisher or playin for fun... if u r playing for fun then i suggest u play some1 around ur rating... playin some1 900+ is brill for improving but every1 likes to win sometimes!

 Yes I am. Coordinates confuse me when I'm black.

At g4 white had the option of h3 and I would be back in the same situation. 

The plan 7...Bg4 8.h3 Bxf3 looks like a good idea, especially since it's your bad bishop, White already castled kingside, and his queen's on d1. Since you have a kingside fianchetto 8.h3 practically forces 8...Bxf3. Believe it or not, you will face these same decisions game after game. It would be well worth your time to really try to understand this position and work through some variations.