As awkward as it may seem at first, usually the best way to ask is just to come right out and ask. Look back through the archives of our own blog for some examples of this. Like, “If there was one thing you could change about SupportTrio…” When people invest financially in your products and services, they often become personally invested as well. This is because they want to feel like they have made a good decision. And they’re usually brimming with ideas about how they could feel even better about that decision.
 
That’s why I think a suggest a feature page like the one at http://www.activecampaign.com/suggest/ should not just be for software companies. Every company that deals with people should be asking their clients what they want to be offered. Not doing that is like turning down money.

Sell what your customers are buying, or they’ll buy it from someone else.

How do you ask what’s missing from your products or services?