How to Maximize your heroes’ abilities?
To maximize your heroes, they should cast their abilities at least once.
Heroes cast their skills as soon as they fill up 100% of their Mana bar. But How do heroes gain Mana? By taking and receiving damage.
Position your pieces in a way so that they gain mana and survive with enough HP to cast. A dead hero cannot cast his skills after all!
Secondly, consider the AoE coverage of your heroes’ abilities—how many cells does it hit, what shape does it cover, and how long is the range? The more units the skill hits, the better.
There’s probably no better way to learn this than through experience, so during battle phases, make sure to watch carefully and study how units and skills work!