1) Not listening to the customers: If you are not listening to your customer then you are not serious about doing business with them. A sales professional who starts pitching without listening to the customer's requirements is on huge risk of loosing the deal.
2) Not mastering the product/service: If you are not mastering your product or service, then you are not qualified to sell the product/service. As an executive with little knowledge of product/service, you have negligible chances of cracking the deal or closing the sale.
3) Not communicating the value or benefit to the customer: As a sales professional you should communicate the value of your product/service to the customer and should demonstrate how it can help them in their life or business.
4) Failing to capitalize on relationship: Many sales professional develop initial connection with ease and even present the product/service in a more convincing manner but they lack the ability to capitalize on the relationship build over the time. As an able sales professional you should take the customer to the sale by passing on the best value and asking for the referral from their same vertical.
5) Not following up with leads: Many sales professional stop following up with the leads after one or two followups. To become a master sales professional, you should follow up with the clients on regular intervals by offering them various kinds of promotional offers.