As a product manager, you are the person that has to know the product best. That’s why you need to take your time to use, consume or play with your product – you simply can not replace personal experience. After that, list the features of your product. Find out, what its strenghts are. Also, find out which weaknesses your product has http://www.slideshare.net/brainmates/10-tips-on-how-to-be-an-awesome-product-manager