you are the ruler of your keep. Your responsibility is to defend your castle against "The Beast," an evil overlord, and use your "blade of innocence" (metaphorically speaking) to conquer his castle. To do that, you must raise and train your army, and build improvements to your castle. Be sure to use your money wisely, and save up for better improvements whenever possible. For the Very Easy and Easy levels of Blade of Innocence, I recommend starting with the windmill; then build the barracks and get three footmen in place before building the blacksmith shop.
Hacks:
Loads of money,faster build time
Strategy
DFTskillz
*EDIT*
made a hack of my own :P