Try live first, if that doesn't work try frozen/thawed.
I usually try breaking the lizards tail off first and scenting with the blood first.
Next you can try freezing the lizard, once it's frozen open the mouth and rub the pinkies head around inside.
The lizard gut technique hasn't worked that well for me but others have reported it works.
Basicly use any variable you can think of, including environmental. Offer at night, hide box, no hide box, in the cage, in a deli cup, humid cage, dry cage.