Well for starters, I always bring one of those fragile paper play-mats folded in my pocket whenever I go to Leagues or Tournaments. You know, the ones you get from Theme Decks. I've always got my dice and flipping coins in a small plastic bag, in the tiiiniest slot on my backpack. As for in-game, I really try to just think up all my moves hypothetically beforehand, imagining the various tight spots I could get stuck in and try to play generally quickly. This is ESPECIALLY considering how these matches are timed, and what might've been a victory without a time limit, would turn into a defeat with time limit, due to me playing so slow.
I really want to be courteous and hospitable to my opponent, so I don't really tap my finger or make any "impatient" gestures, or anything like that. I do understand playing slower gives rise to suspicions of cheating, though, so maybe I'm acting TOO nice... hmm. It really doesn't bother me that much, though.
Of course when I start playing in online games, my playstyle tends to relax alooot, especially when I'm playing with a close friend, or someone I feel I can trust, because then I care more about having fun and generating fuzzy feelings ***|) .