Ok, I’ll stop posting games unless asked for. But, while I think I made some serious mistakes I won another and am excited.
Black this time
This is to finish the game already partly annotated (as usual my comments are in italics):
and now
Na4 feels like a trap. I don’t know what to do with it. Almost moved b5 but didn’t.
This was probably a mistake. But at the time I felt like centralizing my rooks to the white king side was important. But this is where I feel I lost my momentum.
*Na4 is not a trap. The Knight can go to b6.
(To be honest, playing poor moves just because they might lead to a trap is not good chess. Yes, you’ll beat a few beginners. But if you consistently play good moves, you’ll not only beat beginners, but many other opponents!)
After 11. Na4 b5 is good for two reasons:
*a) There is no setup to trap your Queen
b) a well-supported push in the centre is a good idea
c) where to put your rooks is an interesting question. It’s good to think about where you want both of them to go, before you move either
*
13. f4 h5??
Crap
13. … Qg6 is fine for you. (If 14. f5 Qg5.)
14 fxg5 and White is winning
Enjoy the feeling! 
2. … f6 is not good. It blocks the Knight coming to f6 and opens the line h5-e8, exposing the King.
White can try 3. Nxe5 when 3. … fxe5?? loses after 4. Qh5+, but 3. … Qe7 wins back the pawn.
h3 is unnecessary - it’s important not to waste time in chess. 4. d4 was better, challenging in the centre and opening a line for the bishop on c1.
… h5? doesn’t develop a piece, control the centre or help castling. It simply weakens Black’s position.*
O-O b6
Oh dear. While White plays good moves, Black is moving pawns for no good reason.*
Finally Black develops a piece. However since this allows checkmate in two moves, it’s a blunder!
8. Bf7+ Kd7 (forced)
9. Qe6 mate
1-0
*It’s interesting that Black can’t play 9. … b5 (a fork) because 10. Bxb5! wins a pawn as the a6 pawn is pinned. (If 10. … axb5? 11. Qxa8.)
… a5 is another poor move - develop a piece!*
d4 Bd7
Bb5 g5?
Stop moving so many pawns in the opening!
12. … dxe5 or 12. … Nxe5 don’t lose a pawn.
This loses a pawn, since the Knight on e7 is pinned.
This loses a queen, since the Knight on e7 is pinned.
White played well and deserved to win. 
It’s interesting that my basic advice (control centre; develop pieces; get castled and check your move isn’t a blunder) was not followed by Black who therefore lost quickly.
Well this thread plus the book Everyone’s 2nd Chess book, have been helpful in getting me to see things better.
I have played several more games with my friend (we essentially start a new game as soon as the old one ends.)
I have questions about 2 of them. In both cases I feel like I put myself into a strong position going into the middle game and then failed to capitalize properly. In one it resulted in a loss. In the other I still won, but it was more hard fought than it should have been.
I would love it of you guys could give me some feedback on where I went wrong (of if I actually did). I can annotate the games if you think it’s helpful, but I’m not sure it would be. Let me know?
This one I’m Black. I felt like I was doing significantly better until around move 12 or so, then it sort of all fell apart.
Here I’m white and had the game in hand the whole time, but I feel like I should have put it away sooner than I did. Maybe I couldn’t, but it felt like I let him hang in longer than I should have.
In the first game, you’re right that you were significantly better early on. Your mistake was not dealing with the attack on your h-pawn from his knight and bishop. Something like f6, g6, or h6 on move 17 would have blocked out his attack. Then when he took with Nxh7, you needed to move your rook away rather than playing Kh8. Losing the h-pawn wasn’t the end of the world, but losing the rook is a big problem. It almost looks like you were expecting him to take your pawn with Bxh7+, and you’d have to move your king, so you did that anyway when he took with the knight instead?
In the second game I didn’t see anything obvious that would have ended the game quicker. That really doesn’t matter too much, though. Once you won his queen (nice tactic) you should just play to avoid giving him any counterplay. When you’re so far ahead in material, you can just trade everything off, even if the trades are marginally bad for you, and win easily with your extra material.
When the two players castle on opposite sides like that, it’s often good to push your pawns towards the enemy king, since you aren’t exposing your own king by doing so. If I were playing black in this second game, I would probably have played some kind of g5/h5/g4 moves soon after castling, almost without thinking. I’m not sure whether they’re the best moves, but it’s a natural attack to play.