Eros learned to potty in his litter box with just praise, kisses, and petting. When I'm teaching him things like tricks though I like to use the Itty Bitty Buddy Biscuits by Cloud Star that I get at Petsmart since they look tiny gingerbread men, and I break them up into even smaller bites for training sometimes. They come in several flavors and don't contain corn, artificial coloring, and you can also get them in wheat free flavors. That is all important to me because Eros is a Maltese and artificial coloring, corn, etc. is horrible for their tear staining. This site has several versions of these treats and even lets you buy them in bulk
https://www9.mailordercentral.com/cl...?number=W12X30 
Desiree & Eros