When in battle, send a couple of soldiers at first for defense, then let your mana build so that you can upgrade your mana tower. The more upgrades you do to the mana tower, the quicker the mana will build and the more it can hold, for that reason the quicker you can launch soldiers after that. If you have an exceptionally rare character who takes hundreds of mana to launch, this is particularly relevant. You'll need to send just enough to hold the enemy at bay for some time, however then once you send your heavy player, the battle will be over very rapidly. To safeguard throughout the waiting time ahead of time your best choice is to use the up and down buttons to intend the arrows being launched from your tower.