Michael D'Antonio, the author of " The Truth About Trump ," is writing Trump Watch , a series of columns on President-elect Donald Trump for CNN Opinion. The opinions expressed in this commentary are his.

(CNN) Before his election, the closest Donald Trump got to the presidency was on an episode of "The Simpsons " television show, which forecast a dystopian future when he would occupy the Oval Office.

Now, he is the president-elect, due to occupy the most powerful job in the world beginning January 20. Trump may be the most unconventional and perhaps the most controversial man ever elected to the White House. Since he's someone whose policy positions and style are completely different from the presidents of recent decades and is known for his unpredictability, his election presents the nearly seven billion people who share the planet with him with a most difficult question: How do you deal with Donald Trump?

Trump has long vexed those who would work with him, compete against him or even seek to understand him. On a personal level, his first wife Ivana, who has known him for forty years, told me that even after raising three children with Trump she doesn't "get him" at all. His critics in business and politics have complained that Trump changes direction so often it's hard to get a reliable fix on him. He nevertheless made a success of his third marriage and despite bankruptcies, he's always found new partners for his ventures.

A wild card dealt to foreign leaders

Confronted with a president who has the thinnest resume in history -- no record in government, the military, or any other form of public service -- world leaders are already straining to adapt to Trump's improvisational style. The president elect hasn't waited for briefings from the State Department, which typically helps incoming presidents. And he hasn't shown much interest in diplomatic tradition. Instead he has made a flurry of calls to other heads of state and received incoming contacts like a short order cook -- first come, first served.

Australian Prime Minister Malcolm Turnbull swerved around the usual protocol for contacts with America's closest allies -- the United Kingdom usually comes first -- and reached Trump by dialing a phone number he got from pro golfer Greg Norman. Just as remarkable is that fact that instead of waiting to hear congratulations from abroad, it was Trump who started calling presidents and prime ministers . Ireland's Prime Minister Enda Kenny was the first European leader he spoke to, apparently because his adviser Rudolph Giuliani is well connected to the Irish Consulate in New York.

Any world leader wondering about how to connect with Trump should take a hint from Japan's Prime Minister Shinzo Abe , who jetted to New York from meetings in Peru in order to speak with the President-elect directly. Abe is no doubt aware of Trump's past record of Japan-bashing -- before he attacked China's trade practices Trump made the Japanese the enemy -- but he has not made a public issue out of this history or Trump's suggestion, during the campaign, that Japan pay more for the defenses provided by the United States military and, perhaps, acquire nuclear weapons

A lifelong salesman who values the personal touch, Trump is unafraid to negotiate on an impromptu basis and prefers to meet with people face-to-face or speak to them on the phone (He does not enjoy reading long memos or proposals). If Abe pointed out that he has already increased (modestly) Japan's defense spending and that his country can be a counterweight against China, Trump will be impressed.

The political is personal

Whether he was acting on the basis of intuition, or research into Trump's modus operandi, Abe was right to use the idea that he was in the neighborhood, well, at least the hemisphere, to justify popping-in at Trump Tower. Always partial to the person who hustles ahead of others, Trump also believes that he is a great judge of human beings and that he can determine in an instant whether he's dealing with someone he can trust.

In my conversations with Trump, he criticized Barack Obama for failing to operate in the same way. He thought his predecessor should have met more frequently with members of Congress in order to cultivate productive relationships with them.

Congressional leaders who would get along with Trump would do best to follow Abe's example and make the effort to spend time with the man. Representatives from states that profit by foreign trade -- Texas, New York, California, etc. -- would do well to tell Trump about it before he acts to make his campaign promises come true. The same goes for those who would like to protect as much of Obamacare as possible.

When Trump sat down with President Obama last week to discuss just what it is the president does -- he and his team have seemed unsteady on this matter -- he heard a pitch for keeping parts of it. Apparently persuaded, Trump soon said he'd like to keep certain popular provisions, like guaranteeing insurance for people with pre-existing conditions.

Exasperating as it may be to learn that a man who ran for president by attacking Obamacare only now seems to understand it, Trump's change-of-heart speaks to the importance of making personal appeals in order to influence his politics. As a pragmatist who was a registered Democra t from 2001 to 2009, Trump is not a lifelong Republican, nor does he take consistently hard-right positions on issues.

During the Republican Presidential Debate in Houston , he was criticized by opponents when he said government should make sure poor people get life-saving medical care. As Senator Ted Cruz sputtered, about this idea being tantamount to socialism Trump said, "Call it what you want, people are not going to be dying on the sidewalk." It was hardly a hero's stand on behalf of the poor, but in a party that includes some anti-government extremists, it revealed Trump's comparative flexibility.

He can be co-opted

It is the flexible, some would say equivocating, side of Trump that members of the House and Senate might seek out during the transition and when he assumes power. No one knows this better than New York Senator Charles "Chuck" Schumer, a Democrat who will be take the role of minority leader after Senator Harry Reid of Nevada retires.

Schumer, who has received campaign donations from Trump, has known him for decades. He has signaled that rather than oppose the new president on everything, as House Republicans determined to do when Obama was first elected, he will seek common ground on issues such as public works projects, paid maternity leave, and child tax credits.

If they can make common cause with Trump on issues that matter to their own supporters, and, in their mind, to the United States as a whole, Democrats might be able to triangulate the Tea Party members of the GOP and others who are rigidly anti-spending and consider everything that Obama touched to be anathema.

For his part, Trump has always appreciated the value of leverage, in the form of the heavy debt he has sometimes placed on his companies. He won't be afraid of adding to the national debt if he believes the spending is an investment that will pay dividends in the form of eventual higher tax returns that one day can stanch the red ink.

In the meantime, he would be able to goose the economy, especially if he slashes taxes, and create at least the impression that he's doing a good job for Middle America. Long a man who appreciates the appearance of success almost as much as success itself, Trump will gladly team with Democrats against hardliners in his party if the rewards are right.

Fight when you must

Never inclined to leave anything on the table, Trump can be expected to push as hard as he can for his agenda. He is also willing to frighten everyone in sight if it gives him a tactical advantage. This may be why he gave one of the top positions in the White House to Steve Bannon , who was in charge of Breitbart.com, which has published anti-Semitic and misogynistic posts.

Bannon is a leader of the so-called alt-right, which is regarded by large numbers of Republicans as well as Democrats as a dangerous white nationalist movement . Bannon's appointment could have been a sop to this tiny portion of the electorate or he could constitute a kind of human threat, poised to carry out the most extreme policies in the agenda Trump presented during the campaign.

Perhaps the most extreme of these ideas is Trump's call for mass deportation of undocumented Mexican immigrants, many of whom have lived many years in the U.S. and have deep roots in local communities. Others that lurk outside the realm of decency, and perhaps the law, include a ban on Muslims entering the United States. Trump has, himself, backed away at least in part from these ideas.

However Bannon's appointment may indicate otherwise. Should Trump light a match and turn toward the most divisive policy proposals of the campaign, either because he believes they are right for the country or that they make for good politics, opponents must consider themselves to be swimmers confronted by a menacing shark. If all else fails, punch him in the nose.

Although Trump says he never backs down, of course he sometimes does . Among the few publicly available records of Trump's past one can find accounts of lawsuits he has settled in order to end a conflict. In one of the few that involved a public policy issue, Trump settled a claim the Justice department brought against the family business for racial discrimination against lease applicants by agreeing to change practices. Recently the New York Daily News reported that Trump is ready to settle the big fraud lawsuit filed against his so-called university in federal court. (On Friday, Trump agreed to pay $25 million to settle three lawsuits against Trump University.)

Bring a celebrity, and shake his hand

Although Trump was once a renowned germophobe who avoided shaking hands, he is more or less over that little foible. In fact, he enjoys interacting with the stream of visitors who have trekked to Trump Tower over the years and has always considered himself the kind of man who keeps his word, especially when a handshake is involved.

A good example is the story he tells about how he negotiated the deal for his TV show "The Apprentice." As he explained to me, the entire arrangement was worked out in a single face-to-face meeting with producer Mark Burnett. The result was a lucrative arrangement for both men, which endured for more than a decade and brought Trump into millions of American living rooms.

For members of Congress, foreign diplomats and other leaders who must deal with Trump, face-to-face negotiation concluded with a look-him-in-the-eye handshake will be essential. Trump revels in duels that involve cagey lawyers and complex contracts, and always looks for escape clauses that let him do whatever he wants. However, he also fancies himself a man who keeps the promises he makes.

Finally, it's noteworthy that in a frenzied week of serious challenges, Trump nevertheless took time to interact with a world-renowned boxer, a TV judge, a pro skateboarder, and television host Piers Morgan. Always inclined to bask in the glow of other famous people, Trump apparently retains his fascination with celebrities. Anyone who seeks an audience, and influence with him would do well to bring one along.