I've seen a lot of advice on making decks on The Pojo, but not many articles about while you're playing, so I came up with some tips.
 
1. If you get a really good card, act like you're playing poker! Bluff!  Fidget a little in your seat, look worriedly at your active pokemon, even bite your fingernails.  This will lull them into a false sense of security.
 
2. Complain about your deck.  Make it seem like you have no energys, or something like that. Lay some weak pokemon on the bench to make it seem as if you have no good ones, however, keep at least one good one on the bench so that you'll have it ready, just in case.
 
3. If you have a pokemon breeder, don't act like it!  Keep it until they are least aware. Imagine a Charizard against a Machop!
 
4.  Guard your cards.  Hold them close together, so that they won't be able to see them. When you draw a card, keep them close to you so your opponent will not see them. 
 
Well, i hope this helps!
-Israel Sundseth
http://members.xoom.com/pokeanime
israelmac@hotmail.com
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