To catch a hamster you must first think like a hamster. To do this you may need to live as a hamster for a week or two. You should eat what a hamster eats, sleep where a hamster sleeps, go to the bathroom like a hamster does and you could also try having wild hamster sex. All of these will allow you to think more like a hamster and thus increase exponentially your chances of finding your missing hamster.

There is also the hi-tech approach. Simply strap a radio beacon of small proportions onto your hamsters back. This will make the hamster much easier to track down should it somehow escape.

Maybe if your hamster is into bongs you could try leaving some laying around along with some munchies, this may draw the little guy or girl out.