What are the selling skills of self ?

First of all, you need to know your self: strengths, weaknesses, needs, knowledge, passion, ...etc.

Then and after the knowledge and analysis of these parameters you can put the plan how to sell your self and always to be presentable and polite and these comes after being honest with your self and believe in your self and your strength that comes also by continuous self development by self learning, asking for knowledge and expertise from whom are more experience and real trustee resources.