How you identify the needs and wants of the internal customer of the hair salon?

If you already own a salon, some of the basic information is already there such as customer numbers, age range, frequency of visit and average spend. To build on this, would it be feasible for clients to visit more frequently? Frequent visit discounts might be useful here. Do we offer additional services such as the latest highlights at every visit? Do we always ensure that appropriate home hair care items such as shampoo etc are offered and promoted at the end of each visit, having mentioned them and their key benefits during the visit to sow the seeds of interest? How could we attract a wider age range if the current clients are at one end of the scale or the other? Does every client have their next appointment booked prior to leaving the salon as statistics show between 50 and 75% of pre booked appointment's are kept? Could existing customers become ambassadors for the business by bringing a friend for a hair dressing session next time with a thank you discount? Could we have a customer feedback form which customers could complete and add their comments to? Nothing too heavy here, its not the Spanish Inquisition, just looking for customer feedback to help us do things even better in the future.

I would add that I know nothing sbout hairdressing, but business is the same everywhere. Find what works and do more of it!