Your BEST strategy in the "interested" phase is to make sure the potty doesn't become a scarey place OR a place associated with pressure. Just say "Let's try", at this point if she goes it's most likely an accident but the first accident that she associates with a GOOD JOB will encourage her to do more going forward. Periodically throughout the day just say "Hey let's try" I always say, "Let's sit on the potty and sing the alphabet." One round of the alphabet and that's it, no pressure, no prolonged sitting on the potty.

And of course M&M's work WONDERS too! Good luck!