I use a single treble quite often, and since we can only use dead baits here I like to center punch my baits, that way the fish should get the hooks right in the mouth.
In the second method I wrap an elastic band around my baits a few times and then run the loops through the 3 trebles on the hook to keep it on, that way the hooks are fully exposed. A red elastic band is preferred for an injured look, but the other colors will do in a pinch.
The last method is to hook one of the trebles through the back right in the middle of the bait.
WW