What makes a good salesman?

I work as a technical guy and also coordinate with salesmen. Doing sales technical support, I have the opportunity to observe salesmen working when I go to meetings with them.

At times, I wonder why other salesmen can make and close deals compared to others. Why would these salesmen can close that deal? This question always flash in my mind when I go for meeting.

I sort of conclude that to be a good salesman, someone has to have some qualities:
1. Committed. This means that the person has conviction to make sales, not just for the sake of selling because that's his job, but commit himself to close the deal. I often went with salesmen and realized that they're not just ready to close the deal, but they talk uncommitted.

2. Understanding of the product. The person must have at least 80% knowledge of the overall product. If he doesn't even know his own product, how would the buyer expect to know the product?!

3. Understanding of market segment. He must know the market trend and his target segment, otherwise he'll be just talking to people nonsense.

4. Common sense. A factor that everyone has supposed to have, unfortunately common sense is not common after all.

5. Persuasive. He must be able to convince people. This quality usually depends on the other qualities stated above.

6. Honest. He can't promise heaven and earth to the potential buyer. He should be honest enough to tell people that the product has limitations. Every product has limitations, so it's not bad to tell the truth.

When I had a discussion with the boss few days back, I realized that they're putting the wrong sales people. These guys in sales post don't even have common sense to know what they're exactly supposed to do!!! They're just good at talking! No action , talk only (NATO) people! What a disappointment!!!