How can we assure that our front liners in Customer Service are adept and fitted for the post?

This seems like such a simple, obvious component to effective customer interactions, but sadly, it is one that is often overlooked today. Train your employees to greet every customer with a warm smile and a question like "May I help you?" You might be downright surprised at how these simple gestures can make your customers' day.

I use a "trial cusotmer interaction experience" in how I determine this - I have the prospective CSR act out an imitation (pretend in controlled environment)  in three different senireos, face to face and on the phone - dependent on the requirement.  

From that I can easily gauge how they will perfrom

There could be several suggestions like place/fix "small mirror" on their desk wall or desk top screen and ask them to keep eye on it while talking with the customers, hence she/he will see how they look a like while talking with the customers. Same time, before, starting the work, make a short sessions where advise them remain cool, calm, soft spoken, problem solver and keen to helpful.

Thanks

I support Mr. Manzoors answer

Regards