The Hero Hall and a Guild Hall are required for your army. Mortars, Cannons and Sniper Towers are the best defensive structures. Builder Shacks, Gold Vaults and Gold Mines are important for resources.
Defense
Create a strong defense that will be ready when your town gets attacked. Once built, upgrade them. Keep up the numbers in your army as much as possible. If needed, wait until your force is sufficient for the task at hand.
Gems
Gems are used to shorten the time needed to build new areas and strengthen your defenses in your village. Gems are also used to gamble for additional goods and to compete in the Lords League. Gems can be used to revive heroes and hire builders. Complete the events that become available to get a chance at getting gems as a reward.
Heroes
Win battles to unlock new heroes for purchase. They are rated as normal, good, rare and epic, in order of strength. You can upgrade heroes to make them stronger. You can fuse heroes together to make them more powerful. Fusing will level up more powerful heroes. The more experience your heroes have, the better they will perform.
Rings
Rings are used to purchase hero cards and upgrades. They are awarded after each battle. You can also convert gems into rings.
The Lords League
This feature allows you to fight other teams and earn trophies by collecting the most of souls during battles. The more you collect, the better chance you have of returning and adding more rewards to your supply bin.
Upgrades
If you have the money, keep upgrading your buildings, especially the Town Hall. Upgrading it is often a prerequisite for other upgrades.
Buildings...