With a dip net. Go to any pond, stream or even log-standing puddle with leaf litter on the bottom, and scoop up a netful of leaves and other debris. Sort through this material and you shold have no problem finding them.
If you're in an area with alot of adults flying around, you shouldn't need much luck. There's almost always 2 or 3 in every netful of watterloged leaves when I go out. The problem is, I'm usualy looking for something else!