The simplest, most obvious way to get information about how your employees are feeling is to just ask them. Are they getting what they want out of the employment relationship or is there some gripe about working conditions that you can correct? The most obvious time to do this is if you conduct annual or semi-annual performance reviews, in the context of discussing the employee's pay raise. As a part of that process, you can bring up the issue of what the employee likes and dislikes about the job, and the general working environment.