Here are several excerpts from an article by Bill Brooks, CEO of The Brooks Group, a sales management and training firm, The Ten Dumbest Things Salespeople Do:

The truth is, knowing what not to do in sales is just as powerful as knowing what to do. I’ve assembled a list of ten of the dumbest things salespeople do — things that are virtually guaranteed to totally and completely de-rail your selling career.

1. They don’t become students of their craft - These salespeople begin strong selling careers, and they really get into it — but then they go to sleep at the switch and forget to do things like read industry publications or new books by sales masters. They don’t go to sales seminars, listen to audios or view videos on sales-related topics. In short, these salespeople don’t constantly re-invigorate themselves.

2. They don’t “narrowcast” their offering - This means that they don’t become specialists at a particular type of market, or at delivering a specific type of product; they stay generalists.

3. They fail to position themselves correctly - The way people position themselves determines how their prospects and customers see them. In short, people pay attention to people whom they perceive as having something important to say to them.

4. They fail to prospect - This is huge. The biggest cause of failure in sales is having an inadequate supply of qualified prospects. How do you get prospects? Like I said above — host informational sessions for prospective clients, send mailings with targeted lists, speak at association meetings, host user’s groups, or offer a webinar.

5. They get in front of the wrong people - There’s an old statement that goes: “You can’t get rich selling to the wrong people.” It is best to be in front of people who: Can make a decision, have a need, have a perceived problem, or pain, and are willing to listen to you.

6. They listen to their peers - Listening to your peers often means you get too much negative input. It is important to understand that 80 percent of your peers are only delivering 20 percent of the results. And you know what? They’ve got nothing better to do than hope you’re not successful, either — so it’s not logical to accept their advice. Instead, listen to positive, upbeat advice that makes you feel good, and think clearly.

7. They don’t understand the economics of their product or service - Would you sell something for a buck and a half that cost you a buck? No you wouldn’t, but unfortunately several salespeople don’t understand value costing, and that’s exactly what they end up doing! These salespeople don’t truly understand what it costs to deploy their solutions in the field. They don’t understand the expense of telephones, manufacturing, advertising, marketing and promotion, so they end up giving the product or service away.

8. They mentally spend their income, before they earn it - If your pay plan is somehow designed to reward you for production or performance — not just a base salary for being around — listen to me. The sale is not made until you have received your commission check and it’s gone into the bank, and it’s cleared — only then is the sale consummated.

9. They fail to ask the right questions - In fact, they may have failed to ask questions at all. Or worse, they did ask questions, but didn’t listen to the answers.

10. They are either digitally compulsive or digitally impaired - In other words, they are so compulsive about digital technology that they spend all of their time on the Internet, or in sales force automation products. Either that, or they’re so impaired that they’re absolutely frozen about utilizing it. As simple, basic and fundamental as it sounds, the truth is — the most successful person is going to be the one who’s going to be in the middle. Bottom line: You should not be sitting in front of your computer screen all day long; you need to be eyeball to eyeball with prospects and customers.