People who recognize their ethical duties, often choose ethically correct actions. Certain correct actions are basically inherently ethical.
Our actions should express respect for persons. When we are honest with people, it expresses respect for them. People trust us because of our honesty and they prefer us for exercising goodwill.
We should keep our promises and should not impose sufferings on other people. It is a universal principle that when we keep our promises, we extend the gratitude and it further extends to more branches, to more people.
Being honest or being fair with people is not so difficult. In fact, it is so very easy to be, and we do not need to be qualified to be fair. It is just a basic idea and it brings a lot in our life and by following this idea, we seek to improve our own intelligence and character.
We should be conventional even when our acts do not have the best consequences in a particular situation, because the general practice produce the most overall good results.