There are several more ways that you can boost your power, so let me go through all of them:

Star up your buddy - increase its power: this can be done by using bless adv. stones and buddy boost items which you can obtain from dungeons! Do this in the Buddy tab, next to the Devour button.

Upgrade your Mount: your mount will need mount orbs or mount bless stones to be upgraded, and you can do that in the Mount tab. Head on there and tap on the Auto button to automatically upgrade your mount!

Upgrade your Wings: the wings will also boost your power, and they will require min wing gems, med wing gems or adv wing gems. They can be upgraded in the Wing tab and you should definitely try to do it.

Boost your Relic: In the Relic tab you can also boost your Relic by using Min Agi Stones, Med Agi Stones or Max Agi Stones. The Relic will also give you a Power boost, along with DEF, AVD and HP.