Keeping your Peridot happy is key to creating a good relationship with your Dot. Dot happiness is shown using the Dot Hunger and Attention meters at the bottom left hand side of the home screen. 

Fill up the Hunger meter by foraging for food and feeding your Dot. Fill up the Attention meter by playing Fetch with your Dot, petting them, or teaching them Tricks.

Keeping the Hunger and Attention meters full ensures you have a happy Dot and allows your Dot to grow!