Strategy

A) Playing components:

Retreating
Magic units can usually deal damage and retreat behind physically stronger units to protect themselves. Sometimes it is better to back a unit away instead of pressing the attack and trading one of your units for an opponent's. Often you can attack an enemy and back off to lure him after your retreating unit to a place where your unit has support and is able to destroy the opponent's unit.

Healing
The longer units stay alive, the more potential they have for damaging the opposition. Also, the longer your cleric stays alive, the longer he can keep restoring health to your team, enabling them to absorb successive pummelling. Clerics support the whole team and are vital to supporting either a sustained attack or defense. use your cleric to heal wounds during the recovery time of various units.

Attacking
When you try to kill an opposing unit, it is often best to go for one unit at a time. Use multiple friendly units to overwhelm the single enemy unit, and this will also spread the retaliating damage between them.

B) Unit playing styles:

Clerics
Kill your enemy's cleric early on in the game if at all possible. Clerics will be killed in two hits even if healed once, by scouts, mud golems, beast riders, golem ambushers, knights, or assassins. Clerics will be killed in one hit by dark magic witches, dragons, empowered dragonspeaker mages and pyromancers (if power above 24) , and lightning wards. You should position your formation to protect you cleric by blocking access to him and placing units in the way of the enemy's potential line of sight. Using double clerics can make all the difference for a Grey account player battling a Gold account one.

Knights
Knights are the guys who do all the heavy hitting. Since they have a very high percentage chance to block, as well as high armour, they are usually placed at the forefront of one's formation where they can block enemies from getting to your more vulnerable magic units. When coupled with the extra armour of a stone golem, or backed by double clerics, knights are extremely difficult to overcome. If a knight is sent after an enemy's cleric, there is a high chance of success, so long as you keep healing and support it with ranged units.

Scout
The scout is commonly labelled a key unit in the game. This is due to his massive range of 6 tiles in a straight line in any movement direction, by 3 diagonal and all in between. Added to his 4 tile movement range, he controls the board being able to move large distances and strike from afar. remember that when you use the scout to attack magic units they will usually be able to make a retaliatory unblockable hit on him. It is good to have your cleric prepared to heal during one of the scout's 1 recovery turn after either moving or attacking, or 2 recovery turns after both moving and attacking.

Scouts have decent front blocking, but can't stand up to repeated hits. Position your scout to one side of your formation for the best chance of being able to attack enemy units from the side. With units that can block, your chances are twice as good when attacking from the sides. The scout is a classic cleric killer because he can get the job done from up to six squares away in only 2 attacks wether or not the cleric is healed.