Don’t forget about providing value

As if you don't know it, providing a value to your product will make it sell good and will make it last. Make sure you know your target customer and you satisfy its needs with your product, don't build the product to satisfy your needs. Make it so it is valuable for the targeted customers.

Credits go to:
http://www.sitepoint.com/blogs/2006/02/10/dont-forget-about-providing-value/