13k game - What went wrong?

Hi. I played this game and lost by 13.5 points. I cannot see any obvious mistakes in my play. The game appears rather peaceful even though I tried to invade when possible. What went wrong? How can I improve?

Hi Ralph, thanks again for the game. As you say it was pretty close.

I think I managed to get the advantage in the center of the board. In particular through moves 73-77 and 88-94 I managed to build territory more quickly than you. Otherwise it was about even.

Thanks also to Senffarbe for your Review. I would also be interested in reading what anyone else thinks about this game.