On turn 5 you could have bought a cellar and I think it would have been useful.
On turn 7 you can play the cards differently for different results. You could play the hunting party first and keep the market square in hand with an option to gain a gold. You could play the throne on the moneylender to trash two copper. I think both would have been stronger than your result, trashing one copper and buying one hunting party.
Turn 11 you buy a gold but I think you should now be creating an engine that can gain, draw, and trash in the same turn. This needs lots of action cards and the gold should be gained with the market squares. In fact, your opponent doesn't buy a single treasure all game and this is why he won.