Weirdly with the really competent magicians, the best way to get an idea how they did it is to not actually pay attention to what they're doing.
Like, if you spot one hand hovering close to one of their pockets while they're trying to distract you with a monologue, then (assuming the magician isn't just shit, of course), they
want
you to spot that and assume that it's something to do with the trick, so really you can discount that pocket entirely from having anything to do with it.
The way they are constantly talking with the audience or monologuing during a trick is very obviously a distraction, but usually they know that you know that so throw in other layers of distraction.
There used to be a dude who would hang around outside the bars in my local town centre, doing card tricks for the smokers outside for tips. The trick he was most fond of had him shuffling the deck at the start while he was chatting with you about your night and so on - the eagle-eyed (and more sober) marks might notice that one of the cards was slightly dog-eared at the corner, and when shuffling he would hang on that one for just a fraction of a second longer. That card has literally
nothing
to do with the trick at all, but once you've been "smart" enough to spot it it's hard to pay attention to anything else.
http://i.imgur.com/6eF0W.gif