You can try toilet treats! and or a chart where she can put a sticker on everytime she uses the toilet :) that's what i do with the children i babysit and they seem to love it!
Just make it fun and make her feel like a big girl when she goes and make a big deal about it like clap say good job ect that what we did 😊 we also didn't use the baby potty we bought the thing that goes on the toilet