agh still no comments :(
My Game
Black has a very serious problem after 18.Nf5. There seems to be no way out. Black could immediately give up. But maybe 18...Rd8 can delay the game. After 19. Nd6+ Kf8 20. N:c4 R:d2 21. N:d2 black has lost a Rook but seems to be "alive".
thats an interesting possibility... but black is still dead meat after Qxd8+ Bxd8 and then white forks black's queen and king into a hopeless endgame for black.
to answer your questions:
Before starting the game, my plan was the same as always: I always try to play for the win, and I always go out looking to control the center, even at the cost of my pawn structure or even 1 or 2 pawns. The reason I always look for the center is because I am generally more tactical than strategic, and controlling the center allows stronger attacks and combinations.
I decided to double major after b5, because the move weakened the c6 square and gave me ideas for combinative sacrifices, like something involving nxb5 or even nxe6 with a strong attack from the rook, the queen, and the bishop.
After black recaptured the pawn, I was going to bring the rook on the deliberately opended f-file and attack the kingside, as I was safe on the queenside. I would then bring over the bishop and the queen, resulting in a strong attack. That might or might not work, but I thought it was worth a try.
After 15... Qxc4? I saw that I needed to move Bg5 to set up a combination. The knight was in the way, so if I eliminated it, I could make almost any move with my knight and the d7 square would be unprotected so my queen could swoop down. I only saw the actual move nf6 after the blunder Be7.
thats an interesting possibility... but black is still dead meat after Qxd8+ Bxd8 and then white forks black's queen and king into a hopeless endgame for black.
You're right, the fork still works und as far as I can see black has to resign here. Blacks main error was to open up and give up the d-file and leaving the king in the centre. The first 8 moves are well played by both, sth. like Scheveningen Variation. But I think that black was wrong with 9. Qc7. To attack your knight it just needed to move 9.b4 and e.g. after 10. Ba4+ Nbd7 black has a great opportunity to attack the white centre with his bishop and still has a strong d-file.

This is a game of mine. Feel free to comment on the sizzling finish!