Do a good job of watching as you siphon the brew. If the hops are in pellet form, it should be pretty easy. If whole hops, you might want to cover the end of the racking cane with something to help keep the hops out of it (you have several options, most of them posted in threads already).
I dry hop in keg, which (IMO) gives a much better result. Not only does it give the hop flavor/aroma I desire, it also keeps it stable for the entire keg. I simply put the [whole] hops into a nylon hop bag (sanitized of course) then place that into the keg right before it goes into my brew fridge for chilling and carbonating. The flavor/aroma from the dry hopping (this way) remains for the entire keg. It doesn't go 'bad' in there if it takes me more than a week (or two) to finish the keg off. I've had whole hops in the chilled keg for 4-6 weeks and the brew was great for the entire time. Sure, you could remove the hop bag after a few weeks, if you wish, but you don't have to.