Try to have a cleric with Mass Regenerate ability to make it easy to survive while facing multiple heroes that you wish to use 4 tries to capture an enemy hero.
Capturing Rare heroes to use for Fortify seems to work the best as they provide good XP while having good capture rate at 25%.
Always make sure you have empty slots in your hero library. If you run out, you will not be able to capture any heroes, regardless of their capture chance!
Capturing heroes that are 1-Star in their evolution are easier to capture than those that are further in their evolution path.
Try to get a cleric quickly as it will save you lots of coins as you won't need to buy potions. Duskwing is a great epic cleric you can get early on. If you also have a lot of friends you can summon the Confessor for another good Cleric early.
While on an adventure, whenever a squad member levels up, their health will return to full or is revived when dead! Pay attention to this (Saves Potions and Money). The Energy Bar and Arena Energy Bar is also refilled whenever your Commander levels up.
You earn coins through regular battles when you are exploring also you get a bonus for completing a dungeon (Where Coin Scavenger Comes Into Play).
Equip a Rogue in your squad and go steal from all opponent's for quicker coins.
Opening your item bag and tapping on a potion will allow you to use that potion instead of the "optimized" choice above a damaged hero's head.
Do not obtain more than 100 potions of any given type, the excess potions will be deleted!
The Caverns of Illusion
This dungeon is only for the best and highest level players, and even then, it still proves a challenge. Even with a full Level 100 team. The gear rewards are worth it if you make it to the very end. It takes about 200 steps to complete. It's highly suggested that you have access to a lot of potions and resurrection scrolls, and a lot of coins banked before going in. You can leave the dungeon with around 25 normal chests, and 8 rare chests which consist of level 75 and 99 gear.