Any producer and developer can do this to improve sales. Simply send an email to your existing customers and you can get tons of information to improve sales. Many people are happy to help you out even if you don’t give them any incentive (like free expansion pack for those who answer).
Ask these questions from your customers:
1) How did you found out about the game? (The purpose of this question is to know where to advertise more. When I’ve asked this question, I’ve got pretty interesting clues on which places are important for gaining traffic. Helps you to know where to focus.)
2) Why did you buy the game? (This is perhaps the most important question to ask, and it can reveal you a loads of things that you never guessed. People don’t necessarily buy the game because you put tons of features in it. They might bought it because they thought it was fun and had cute creatures in it.)
3) How you would like to improve the game? (Only ask this if you actually plan to do something with the answers. If you want to know how to improve the game, the people who actually bought the product are a really good source for ideas.)
With just these 3 questions, you’ve done a better job than the 80% of other companies in this planet (who don’t ask these questions).