I'm wondering how I do this, because I have been since I started. I will make a few final tables and the small stakes, build a few hundred $ bankroll up, and then lose it all on cash tables. Sometimes I move up in stakes, which I know is just stupid, but other times I will stay at whatever is comfortable and just spiral down to $0. I must have done this at least 10 times.
I know I haven't posted much as far as hand history on this site, partly because I have always thought I was mathematically inclined and therefore too brilliant to lose, or didn't want to waste people times with stupid questions, and, more recently, I have no idea where to start. I've been trying omaha, because it keeps my interest going.

I know it sounds ranty but I'm down ~$200 and frustrated.

One of the most humbling days I ever had was when I realised that I could count at least 10 different types of NLH. Tournament, cash, SNG, MTT, satellites, DoN, uNl, Rebuy, etc....

Tournaments are different than cash. One of the primary reasons, imo, is that if you are knocked out of a tourney, you are done. Time to start over. Cash, you just reload and keep going. Cash is about +ev, +BB/100. Tourney is all about being in the money, and the calculated risks you need to take to get there.

If you are successful at tourney, focus on what you need to different at cash, not what you do the same.

I know, dumb advice. But it is not the same game.

dirtlad nailed it,

It's a very different game and requires different skill sets.

In a tournament you need to be able to:
-Adjust to constantly changing stack sizes
-Play a short-medium stacked game (20-40 bbs)
-Make good pre-flop / flop decisions

In a cash game you need to be able to:
-Play poker