Spar, spar, spar, spar some more, that's the most effective way to get over the adrenaline dump. Of course you should only start sparrign after you have had 2 or 3 months of training just in technique and drills. Best thing to do is grapple out of bad positions most of the time and give yourself fewer "tools" then your opponent in stand up training.
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Member of DaJoGen MMA school under Dave Hagen and Team Chaos fight team under Denver Mangiyatan and Chris Toquero, ran out of Zanshin Martial Arts in Salem Oregon: http://www.zanshinarts.org/Home.aspx,