How a customer service deliverer can make a good first impression on a customer?

Greetings, tone, effective listening and respond with possible solutions/suggestions without loss of time. 

First expression is the last expression,

all the customer touch points should be well established/furnished, and the front line soldier of a company i.e. CSR (Customer sale representative) should well Enthusiastic, good speaker and well aware about the company product as well as usual nature of complains. customer should be listen carefully with full consideration without any interruption. try to avoid by using NO YOU ARE WRONG, NOT AGREE WITH YOU, NOT AT ALL, NEVER i mean negative words demotivate the valued customer.  Try to fallow the ask and tell procedure. even if possible make one or two to relevant department in the presence of customer that make him satisfy and try realize him how you are valued customer for us.

at the end good bye to customer with smile face and greeting.

The most basic quality would be to listen first and not interrupt the customer. Also smile when you speak it makes a huge difference even if you are on the phone.