I say that Iam around the same level as you, I can do a wide variety of tricks, mainly card and coin tricks, and (as I do most of my magic in pubs, bars and clubs) I ALWAYS get idiots trying to shuffle the decks, examine the cards, study the coins etc.
There are LOADS of ways that I have used to either
a) throw them off suspecting me
b) make them look REALLY stupid in front of their mates - my personal favourite
a) (as already suggested) p**m the card then pocket it / if you are confident enough, plant it on them
b) this is VERY fun to do, as all of the idiots mates will laugh at them, and will maybe even persuade him to appologise to you - I choose to either place a bet with them (for £5 or a round of drinks etc) and 'obviously' make a mistake, so that they cannot refuse the bet - then (I can't reveal the method here, but can be purchased from lots of places) do any number of 'card to wallet' effects. Thais way, you can 'loose' the bet, then when you go yo get your cash out...bam! their (signed maybe) card is inside your wallet - its a real 'haha he got you, now you look stupid' moment - always fun
