Umm, reading the animal, most importantly--

I have a really tricky girl and I don't notice a difference when I pre-scent for her (sometimes the opposite--she gets confused or something and hides) so I stopped, but prescenting usually brings out my boy who'll come up to the side of the tub to look at me and snatch it up as fast as I can get it near him.

Braining, heating it up to a higher temperature, doing it at night, making sure to keep myself hidden, waiting until they're active. But braining (yuckyuckyuckyuck) is only if she won't take the f/t with just heating.