There are many articles regarding the best traits.

I like Harvard Business Reviews assessment (click on picture for HBR article).

Modesty:

I agree. Ego centric salespeople that want to talk about themselves and their accomplishments are a turn off to the customer. Positioning the team, listening, and openness are some of the key ingredients.

Conscientiousness:

Taking your job seriously and taking the mission seriously.

Achieving:

Being goal oriented and fixated on success is definitely key. Consistent success is difficult without writing goals and envisioning success on a regular basis.

Curiosity:

An interest in learning, understanding, and improvement is a sign of intelligence and a willingness to succeed.

Gregariousness:

Lacking of it. Top salespeople aren’t the most social people in the room. They do and achieve results through action rather than talk and display.

Lack of discouragement:

Never giving up. Driving every day with a consistent and positive attitude, knowing that when one door closes another larger one opens.

Lack of self-consciousness:

A good salesperson can normally live up to the challenge, like a speaking role or a public presentation. Given that at some point everyone makes mistakes, a great salesperson minimizes set backs or learns from mistakes during a meeting or presentation and moves on.

Tony Bilby