You can equip your heroes with troops, then send them out into the world to do battle against roaming players, cities, and computer-controlled demons and demon cities. As they battle they use up supplies, and gain wood and gold. It takes awhile for them to recover, so make the most of the supplies that you have by doing as much battle as you possibly can before you send them back to the city. Since Grunts can be set to go for either gold or wood it's best to maximize the amount of grunts that you have at a time, so that you can load up on the resources. Free gems: complete the quests, connect to Facebook via the game and you will earn plenty of free gems. If you are sick of battling or you just want to load up on free goods and troops, look for as many ruins as possible. Land your heroes on one of the ruins, and you will ll pick up a significant amount of free wood and gold, as well as some free troops occasionally.