Completing Tasks
Sometimes, Hints are rewarded for completing Tasks

Opening Chests or Big Chests
Occasionally, Hints can be found in Chests and Big Chests

Using your Coins
When you run out of Hints, you can use your Coins to get more hints. The amount of Coins to get a Hint is always shown directly underneath the Hint Button.

Purchase a deal - like the Starter Pack
Deals are a great way to get a bunch of extra Hints, look for deals in the shop regularly.