Protecting your empire, your troops, and your resources is extremely important in Game of War: Fire Age. One or two (or a few) attacks from other players, or from an entire alliance, can turn your city into a smoldering pile of rubble (at least temporarily), along with destroying all of your troops, stealing your resources (especially your silver), and making it difficult to recover. Read on for some tips on defending your city from invaders!
Training troops is the first step to defeating your empire, but upgrading your wall and training traps is just as important, if not even moreso. There is a ton of research you can do in the academy, which is required to train any of the traps other than war bricks, but even training thousands of war bricks can go a LONG way towards protecting your resources and your troops.
Hide as many resources as you can by upgrading the warehouse as high as possible. Of course, you can only upgrade your warehouse as high as your stronghold level is upgraded, so upgrade both of them in order to facilitate the warehouse upgrade. Each subsequent upgrade adds 50,000 protected ore, food, wood and stone.
Protecting your troops is done in a few ways. Build and upgrade as many hospitals as you can in order to house more wounded troops, thus ending up with less of your troops getting killed after battles. The traps mentioned above can shield your troops from battle. And finally, occupy an empty space, such as a forest, plain, or mountain, and leave your troops there for as long as you need to. Nobody will want to attack your encampment because it contains no resources, but when your city gets attacked, no troops will be killed.
All of the above strategies will also prevent your hero from getting kidnapped and imprisoned. Plus, if for some reason he does get kidnapped, having more hospitals will give you that many more troops who can go after your hero and break him out of the prison. Stalk your attacker and wait until their troops leave to attack someone else, in order to get an easy battle.
Plus, of course, use your academy to power up both your troops and your traps using research, and to upgrade your troop and trap training speed. Use crafting to create and add equipment to your hero which increases the strength of your troops. This benefits both attack and defense strategies.