Hi, good luck! A few comments on the game you posted:
It's more important to protect your stone in the corner here. 
This move makes what's called an empty triangle (because the three white stones are a triangle, and they're not wrapped around a black stone, and it's often not what you want to do. In this case, it leaves a weak point at C4. It's better to descend to C4 yourself. Black still can't push through, and your two stone groups are less likely to get cut or put into atari. In the game, you play B4, and thereby lose sente (something like "initiative", if you haven't seen the term before). 
This is a natural place to play. 
It's better to play again with your two stones on the right. They're more vulnerable than your two on the bottom. 
E18 would work here. 
You should probably play to strengthen your two isolated stones on the top here. 
What were you hoping for here? 
Good choice. Haven't reviewed past there.