What's your process for incorporating client feedback into a portrait or caricature while maintaining your artistic integrity?

In order to accept a job, there must have been that first communication that determines whether or not I am compatible with what the client is looking for. It is very important for me to deliver, as far as possible, work that exceeds my clients' expectations, or at least manages to translate on paper what they want. Before painting, I usually send them a photo of the main sketch so they can approve or request corrections if necessary, but all of this is only possible if there is initial compatibility.