Mine seem to get the most oomph from 'nip when they can't eat it. I recycle old pantyhose into little catnip sachets for them. I'm paranoid they'll end up eating the hose, so I only give it to them when I'm there to watch. Besides, what fun is giving them catnip if you're not there to watch?!
I also store some toys in a ziplock baggie with some 'nip.
I sprinkled some on her little cushie bed, and she spent most of the night there for a change. I also did like in the pic above, it was funny seeing her try to shove her entire head in a little baggie.