Always stop to collect any Amenoculus, Geoculus, or Electroculus you see floating nearby. These collectibles can be traded into the Statues of the Seven scattered around the world to upgrade them. Doing so gives you a bunch of rewards, including more stamina so you can climb higher or windglide for longer. These guides for Anemoculus (opens in new tab) and Electroculus (opens in new tab) locations should help you out.
Complete all the mini objectives in your Adventurer Handbook. It gives you a ton of resources and helps boost your adventure rank. If you’re lost and unsure of what to do, this is always a great place to look.
A character who uses the greatsword will break rocks way quicker. If you’re going to go mining, bringing a greatsword-wielding party member will help a lot. Failing that, Amber’s Explosive Puppet ability will destroy most ore veins almost instantly.