First, Do No Harm!
This oft attributed phrase to the Hippocratic Oath which is related to doctors can easily apply to sales people.
"It is the duty of every sales person to follow a system and regimen which can benefit their customers as per their ability and judgment and in doing so they should refrain from any actions that cause harm or damage."
The duty of the sales person lies towards:
The Customer
Always have the benefit of the customer at heart.
Use your abilities to ensure the customer receives the best value.
Ensure that the solution you provide is the best available.
Remember that you are there to support and ensure that your customer’s business grows.
The Competition
Yes, your competition also needs your care and concern.
Do not put your competition down; remember that your competition enables you to make improve yourself.
Focus on your own product and service and the benefits it can offer.
(If you are ever in doubt of how competitors can survive in the same environment, go out to a park or garden and watch the flowers bloom. While different flowering plants all compete for the same water, nutrients and sunlight, they add beauty to the landscape while equally enabling bees to make honey.)
Yourself
As a sales person you are also responsible to ensure you meet your sales and margins. Do not sell at a price that erodes your margins and therefore harms your company’s bottom line.
Avoid conflicts of interest; when in doubt ask someone in your legal department.
Do not oversell; you will not be able to deliver and therefore cause issues not only for yourself but for your customer.
Do not undersell; remember you need to deliver the best value you can offer to the customer.
As a supplier, you may be privy to the customer’s inner workings; endure to protect their privacy.
Ensure you provide all information to your customer so they can make the best decision for themselves.