Just joined the forumns so I don't know if this is a little late but I've had the same issue with one of my female cane toads.

The breed tends to be overly skiddish for such large toads, at least my two are.

All she'd eat was crickets at first but after a few weeks I started to introduce a few super large meal worms when I added the crickets to the tank. It's best to do this on a flat surface so they have limited places to run/hide/dig away. As much as I wanted some substrate for her to dig in those green and brown tank mats you can get at Petco or Petsmart work great. They also are simple to clean when she produces waste, easily cleaned out in the shower. Cane toads produce a lot of waste so you'll find yourself cleaning the mat at least five times a week.

But yeah, introduce a few of those large meal worms when putting crickets into the tank and she/he will accidentally eat a couple of them thinking they are crickets. Some will move fast enough (like crickets) to get her attention and sooner or later they'll become the staple of her diet rather then the crickets.

After the large meal worms you can move onto slower prey like earth worms. At first they'll have problems with them since they are used to just snapping them up with their tounge. Earth worms don't stick as well so it takes a little more mouth action on their part.

Limiting the stress of the animal really is the key though as mine are/still am overly skiddish. Feed them from above the tank from a direction they can't see you or your arm movements.