I have several applications in the AppStore. Among them is a ballistics calculator that caters to only a small group of people. I've found that the same basic r

I have several applications in the AppStore. Among them is a ballistics calculator that caters to only a small group of people. I've found that the same basic rules apply to the AppStore, that apply elsewhere in life: work hard, design a quality product, and support it... you'll make good money. Word of mouth is the best advertising you can have. Have an occasional sale when sales slow down and that's all you need to know. You don't have to spam, advertise, or write a bunch of useless rubber-dog-poop toys. Just make something that's good quality and keep supporting it.