Customer visits are expensive–and if you don't make a sale, your time and travel expense has been wasted. So you need to make sure you're at your best during face-to-face meetings.

Here are the 10 most common blunders that sellers make during meetings with potential customers. Some may seem obvious--but you'd be surprised how easy it is to stumble into them.

1. Being late to the meeting. If you don’t arrive on time, it tell the customer clearly that you don’t give a hoot about them or their time. Always arrive 15 minutes ahead of time. If you drive to calls, get a GPS device to make sure you won't get lost en route.

2. Failing to check your appearance. Don’t show up with something amiss–spinach in the teeth, lipstick smeared–that could have been headed off by a quick stop in the client’s bathroom. Make a quick pit stop before the call, and give yourself a once-over.

3. Acting way too friendly.  You'll just seem phony and "salesy" if you pretend that a prospect is like a long-lost friend. Approach each prospect with respect and courtesy–not with a glad-hand and a back slap.

4. Talking rather than listening. Sales calls are about relationship building and gathering information. You can’t do either of those if your mouth is moving all the time. Get curious about the customer. Ask questions.

5. Arguing with the customer. If the customer doesn’t agree with an important point, arguing is only going to set that opinion in concrete. Instead, ask the customer why he holds that opinion; then listen.  You might learn something.

6. Giving a traditional sales pitch.  Sure you’ve got something to sell–but nobody wants to hear a sales pitch. Have a discussion about the customer's needs; then, if appropriate, discuss what you've got to sell.

7. Falling short on product knowledge. The prospect doesn’t want to hear, “I need to get back to you about that” ... over and over. Make sure you’re trained on your current products and policies before the call.

8. Getting distracted by your smartphone. Ouch! What were you thinking? No call, email, or message is going to be more important than the real live person in front of you. When you're talking with a prospect, turn off your phone. I mean it.

9. Letting the meeting meander. The customer's time is valuable.  Don't have wandering conversation that slowly gets to the point. Instead, provide a brief agenda of what you're there to discuss, and be sure you stick to that agenda.

10. Overstaying your welcome. Your prospect has hundreds of other things that he or she could be doing, rather than spending time with you. Set a time limit for the meeting and stick to it.

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