Does business live or die based on whom you meet for lunch?

That's an age-old question. I once heard about an entrepreneur who held over 300 business lunches in one year, which meant he was "working" on the weekends (since there are only 260 work days per year). He also said it worked wonders because so many customers and investors heard directly from him about his new company. While it's easy to overstate the value of meeting for lunch, if you avoid these few simple mistakes, they can be incredibly valuable for spreading the word about your endeavors.

1. Not asking about any recent personal developments

It's easy to dive right into the business details. After all, you might be the one paying the bill, and you want the lunch to be worth your time. Not so fast on that one. Remember that business is about building relationships. Ask about the family or any recent trips--something to show you care about that contact as a person and not just a moneymaking machine. Avoid jumping right into the serious stuff.

2. Staring down at your plate

We all need nourishment, right? It's easy to focus on the food when it arrives, especially if you skipped breakfast, but set your hunger aside for the sake of the grand cause. Even when you start digging into that salad, keep focusing as much as possible on those at the lunch and keep asking questions. Don't let the food distract you from the real point of discussing business topics and building rapport with a customer or partner.

3. Not making eye contact

Also, if you focus on your food too much, you might not be making regular eye contact. Be sure to look directly at people and let them know you are interested in participating and want to focus on the topics at hand. Eye contact should be something you think about because it's too easy to get distracted and think about other things that you'll be doing later that day.

4. Getting controversial

I've been at a business lunch where I watched as someone brought up controversial subjects as a way to relieve boredom. It's tempting, because you get to see how people react. And it's entertaining, because the lunch will go much faster when people are spouting off on their opinions. Yet those at your table might leave with a sense of discouragement and hurt feelings (or outright anger). Better to keep things focused.

5. Getting too familiar

I mentioned how you should maintain eye contact and ask personal questions, but avoid getting too personal or prying into sensitive areas. It's fine to ask about vacations and the family, but you want to avoid asking about a trial the person is going through unless you are already friends. The goal is to let people know you care and that you see them as more than a means to an end, not to embarrass anyone.

6. Talking too much

I tend to be an introvert and let others talk, but if I am leading the business lunch, I hate to let conversations dwindle and will fill in the empty space at all costs. Sometimes it's OK to let others think about the topic and speak up when they want to speak. Silence is golden--and a good way to reset the conversation. Most importantly, be sure to ask questions and get people talking. Don't just babble to avoid awkwardness.

7. Feeding one person's ego

It's tempting to focus on the power player at the table and throw softball questions or praise that person's accomplishments. It's a technique to get that person to pay attention to you. It's a bad idea, though, and it can quickly backfire. There are other participants in the conversation, and they'll see what you're doing. Keep things nice and even and get everyone engaged, contributing ideas, and listening.

8. Playing it too cool

It's not a good idea to dominate conversation, but you can also hold back too much and stay cool during the lunch, giving people the impression that you don't really care. I went to a business lunch at CES and found one of the participants to be a little aloof. Keep tracking what people are saying and contribute about the same amount to the topic.

9. Crossing your arms

I'm still working on this one, since it's a bad habit of mine. At lunches, I cross my arms as a gesture of interest. Yet it's widely known to be a put-off to most people, a way of using non-verbal communication to say you are closed off to new ideas. Keep your hands open and your arms at your side to invite any comment and accept any opinion during the lunch.

10. Being overly attentive

You might be working on not crossing your arms and talking too much, which is good. You should stay focused and open to ideas during a lunch. Still, it's possible to be too focused in a way that doesn't appear genuine. It's OK to enjoy your salad as long as you keep up with the conversation. The main lesson here? Just be yourself and stay attentive. You'll want to finish your food and end the lunch at some point.