Just Started Competing, 2x So Far...

I decided to start competing this year, and I figure I'll post all my results and any vids I can get a hold of. Any advice would be more than welcome. I'm gonna explain my background, ask a few questions, and then put my results so far at the bottom of this post. Sorry for the long post, but everyone who puts up their results seems to get awesome advice on here. Thanks in advance for any help.

Some background. I am a white belt because our gym makes you earn blue belt twice (once grey, once blue). I am a grey, and have been training about a year and a half. I usually fight with blue belts at most other gyms, even though I have to compete at white until I move up. My teacher is Eduardo Rocha, 4th deg. BB under Royler, fights under Gracie Humaita. I competed once when I had just started - I won most of my first match, gassed, and lost a close one on questionable scoring. Oh yeah, and my name is Harry.

Questions: I have been pulling 1/2 guard to start all my matches. I am way better on my back, and I rarely feel comfortable enough to jump closed guard without risking the loss of 2 pts when the guy just grabs my knee or something. I also worry, even though my takedowns and defense are alright, that I will gas, or waste 4 minutes of a 5 minute match standing. I can usually sweep fast, and often the guy will burn himself out trying to pass before I do. Still, that leaves a chance as I pull guard for the guy to drop his weight on me and make me defend his pass, and I dont see that many guys at my level do that, so maybe I am missing something, or taking a dumb chance. Also, I realized at the last tourney that I can pass easily and maintain position on most guys, so maybe I could play more top game without gassing (I always worry about that because I have asthma). Any advice on starting matches and bringing them to the ground? How long do you play the TD game, and at what point do you decide you have been on your feet for too much of the match?

Also, there was basically no mat space to warm up, and the spacing between matches was both random and unannounced. How do you guys warm up and stay warm? Do you roll with friends beforehand if you can, or just do calisthenics?

My results so far: This year, I competed 2x, and have fortunately had really good showings. I won the first tourney (a small one at Fight & Fitness in San Fran) with 3 fights, but only fought mediocre because I was really nervous. One was a quick shoulder lock from a triangle, one 9-0 (no adv. pts.), one 5-0 (no adv. pts.) because I was really gassed and just swept, passed, and hung on for dear life.

In the second tourney, Claudio Franca's JJ By The Sea, I won 3 fights, and again nobody scored any pts. or advantages on me. The first match was an instant carni. I pulled 1/2 guard, went straight to kung-fu, feinted a gogo from half-guard, and switched to a carni at about the 15th second. Second match, I was up 12-0 when I hit an armbar from mount. Unfortunately, it was a friend from an affiliate gym, and his arm popped slightly when he tried to roll out - I feel bad, but he says its not too bad. Final match, the guy dominated everyone he faced before me. I pulled 1/2 guard, hit a back-roll sweep, and was up 14-0 or something like that when I got another armbar from mount. I'm psyched so far, and I just need to win 2 more reputable tournaments to get my blue belt.