Life In 19x19

Hello!

I have been a long time lurker of go discussions and now this site and I appreciate everything you guys/girls post about Go. I'm a beginner who has mostly played 9x9 and 13x13 games a few times a week with a good friend I recruited at work. We are both beginners. Now on to the point...

I took the plunge and played my first 19x19 game ever (over board or online) on KGS. Instead of asking for a full game review because the responses would be too much to take it all in, I would like to ask about some particular moves that threw me during the game. I played White.

Move 144-155ish: Black invaded on 143 and ended up making a living shape in my corner. How should I have better reacted to this invasion?

Move 164: Same thing here, I got invaded but this time ended up killing black's shape. I probably got lucky, how should I approach invasions like this?

Move 14: I invaded on move 12 to try to break up the bottom of the board. The reason I made move 14 instead of attaching to the black stone was to try to make some space. Was this good in theory?

Move 50: Just wanted to state that this was my dumbest move of the match. I wasn't sure where to play, I was thinking D7 but then I made a rash decision to extend from Q13.

Thank you for any advice that you can give!

12 Such an invasion is usually better off on the 3rd line. Since then you can make a base
82 taking that stone doesn't look good to me. It allows him to seal you in. I would have played at g4 or perhaps f2. With those black still can't rescue his two stones.
164 That invasion should have lived. You need to protect before he invades. But finding the right timing for that protection is hard.

Welcome to 19x19! Try to finish 100 games as quickly as you can --
9x9, 13x13, or 19x19 all OK. A few ideas:

Thank you both Li Kao and EdLee! Your advice makes sense to me and I will work on incorporating those types of moves into my mind. I have studied your responses and looked up more on the topic of miai. Thanks!

I think playing more and doing a bit of easy tsumego are the things that'll help you most.

I for one played about three games a day during my first year of go. While that's a bit too far on the playing vs studying scale, at least one 19x19 game per game should be good.