Booster buildings are usually decorative, such as a tree or fountain. When placed near other buildings, they will increase their efficiency. Each booster has its own rate. For example, placing a fountain next to a quarry will increase the quarry's production by 6%. Those bonuses will stack with the use of multiple boosters. Plan your town's layout to allow boosters to be placed next to as many of your buildings as possible. One method is to place boosters in the center of a section of land, then place other buildings around it.
Fusion
After reaching level 7 or 8, you will gain the ability to fuse two of the same type of units to create an upgraded version of that same unit. Spend your coins to fuse as much as possible.
Hazards and beneficial items
Random objects will appear outlined in either green or red. Green objects are beneficial, while red objects are harmful must be tapped to keep them harmless. For example, tap the green objects on your side to heal your troops. Tap the red bombs on the enemy side when they are near to damage them.
Projectiles
At times projectiles will be launched at your units and can be seen approaching from the top right corner. Swipe over them to destroy the projectiles and keep your troops from the incoming damage.
Weapon strengths
Lighting is stronger than shield, shield is stronger than sword, and sword is stronger than lighting. Premium units that have the star icon are strong against everything. When you start a fight, you will be able to see what types of units you will be facing.
Boosters...