When I started working for myself, I often felt ill-prepared for certain situations. I had loads of experience managing people, but I often felt I was missing something.

Take negotiating, for example. Sure, I had negotiated before--kind of. But nothing like what I was doing now, making deals and offers on an everyday basis. So I did what any new freelancer would.

I googled: How to negotiate.

After hours of clicking, scanning, reading, and watching, I came across the following lecture that has profoundly influenced how I negotiate to this day. It's by Professor Deepak Malhotra, who teaches negotiation and conflict resolution at Harvard Business School. His talk is actually entitled How to Negotiate Your Job Offer, but many of the principles he emphasizes can help on any type of negotiation. (You can watch the talk in its entirety here.)

Below, I've highlighted 12 of his points, along with my own commentary and some lessons I picked up along the way.

So, 12 tips to negotiating like an old pro:

1. Be likeable.

The more they like you, the more flexible they will be.

2. But they also need to believe you deserve it.

It's not enough that they like you; you need to sell yourself and what you can do for the other side. The problem is, the way you go about doing this can make them like you less. The key is to find the balance between one and two.

3. Make sure you're negotiating with the right person.

There's no point debating what your counterpart has no power over. Make sure you've got the right person to start with.

4. Know what you want.

Zoom out and see the big picture: If they can't give you point a, how can they give you more of point b...or a combination of points b and c?

In other words, if you can't get one thing you want, how can the other side make up for it?

5. Don't negotiate just to negotiate.

Malhotra says that his MBA students have a problem with this: They often go 'bargaining berserk' the first chance they get.

If something is important to you, absolutely negotiate. But don't haggle over every little thing. Fighting to get just a bit more can rub people the wrong way--and can limit your ability to negotiate with the company later...when it may matter more.

6. Have a learning mindset: Understand the person on the other side.

Common sense says to learn as much as you (practically) can about the organization and counterpart you're negotiating with. But how do you continue the learning process, during the negotiation?

If your counterpart says no to something you consider important, try asking: 'Can you help me understand why that's hard to do?' Or... 'Have you ever made this exception? Why did you do it in that case?'

Questions like these help you to see if a 'no' is really a no. And understanding 'why' can sometimes lead to a 'no' becoming a 'yes'.

7. Negotiate multiple issues/interests simultaneously.

Let's say there are four key points you don't like about the opposing offer. You focus on one, and they change it to please you. Then, you mention another. They really want to make a deal, so they change that one, too.

Now you come back to them again. 'Okay, so there's one more thing...'

How would you react if you were on the other side of the table?

Instead, negotiate more than one thing at a time. And don't just prioritize for yourself, make sure they know what your priorities are. Otherwise, they might concede a few things that are easy to give up, feeling that they met you halfway...while you feel that they barely moved.

8. Prepare for the difficult questions.

Them: We know you met with company X on Tuesday. How did that go?

You: (I was hoping they wouldn't ask that.)

If you're not prepared for a tough question, you're probably going to avoid it, get defensive, or sound like you're lying (which you probably are.) None of these are good responses.

When preparing, ask yourself: What questions would put me in a potentially defensive position?

But no matter what, make sure you...

9. Tell the truth.

Malhotra advises: "Resist the temptation to tell even a small lie...Don't get into the habit of just saying whatever needs to be said, just to get the deal done."

I'm a big fan of this advice. Some negotiators will tell you to lie to hide your weaknesses. Of course, common sense discourages sharing every weak point of your position. But I've found that honesty begets honesty: The more transparent you are with the opposite party, the more they will be with you.

The key is to be confident in your Best Alternative To a Negotiated Agreement (BATNA). Many experts preach that BATNA is everything, and I strongly agree with that. The more confidence you have in your alternative, the more transparent you can be, and the easier it is to find a win-win situation.

10. Stay at the table.

When someone says a firm 'no' in a negotiation, what they're actually saying is: 'No. (Today.)'

So if you really need to make a deal happen, but you can't come to terms with the other side, it works in your best interests to keep the negotiation going. Not in the annoying way of calling them up every day: How about now? Or...now?

But their situation can change at any time (as can your own). Maybe they're meeting with a company similar to yours next week, which could go horrible for them. They might now be much more willing to give up things that were previously off the table.

Keep contact with the other party, even if you can't initially make a deal. They might come back to you when you least expect it.

11. Ignore ultimatums.

People don't like ultimatums. Or anything that sounds like an ultimatum.

How do you react if your counterpart says something like 'We will never do x'? Or, 'That's not possible'?

I love Malhotra's response to this:

"If somebody makes an ultimatum in any negotiation, I just ignore it. I pretend it was never said...It's possible that at some point they or someone else will discover that the position they took is going to end up in no deal...The last thing I want them to feel at that point is 'I made this big deal about this ultimatum...and now I'm going to lose face by changing my mind.' "

If they make an ultimatum...I don't make them repeat it: 'I'm sorry, did you say never? Under no circumstances? Are you sure??' No--that's irrelevant! 'The most I might say is: I can see how that might be a difficult thing to do. Now let's talk about x, y, and z.'"

12. Prepare for the unexpected.

In his talk, Malhotra shares one of my favorite anecdotes of all time.

In his prime, championship boxer Mike Tyson was practically unbeatable. During this period, a reporter once asked him:

'Mike, how do you continue to be successful when everyone who comes to fight you has prepared specifically to fight you? They've watched your videos, they've read up on you, they've looked at every piece of every fight you've ever fought. They're coming in specifically with a game plan designed for you. How do you deal with that?'

Iron Mike: "Well, everybody has a plan. Until they get punched in the face."

Truer words were never spoken--in negotiations, as in life. You can strategize as much as you want, but sooner or later, something's going to throw you off your game. So don't give up. Roll with the punches.

Negotiating is no easy business, but I've found these tips invaluable. I hope they work for you, too.

And I hope the punches to the face stay at a minimum.