Editor's note: Columnist and author Helen Thomas, 89, was a United Press International correspondent for 57 years and covered every U.S. president since John F. Kennedy. Craig Crawford is a TV commentator and political writer. They are the authors of "Listen Up, Mr. President: Everything You Always Wanted Your President to Know and Do." (Scribner, 2009)

Washington (CNN) -- We've been watching presidents come and go for years and have come up with five key lessons for President Obama to keep in mind as he copes with the world's toughest job.

Brace yourself: The worst is yet to come

Mr. President, you've probably already realized that your inauguration is likely to be the happiest day of your presidency. If only you could make that feeling last forever. The White House can be one of the loneliest places in the world. Just look at the physical deterioration some have suffered during their years in office.

If you do not want more gray hair, be prepared for a dye job.

Most presidents leave Washington with, at best, mixed feelings toward the place and many with whom they've worked -- especially the press. Perhaps that is why they choose never to live there again after leaving office and visit infrequently.

John F. Kennedy once called Washington a city of "Southern efficiency and Northern charm."

Harry Truman famously said that if you want a friend in Washington, "Get a dog."

Forget your privacy: You are a public servant

Sorry, Mr. President, but when you go into the White House, you had better know that you live in a fishbowl with few hiding places. You are public property. Don't go into public life if you want a private life.

And never forget you are not the boss. You work for the people. Lyndon Johnson might have been joking, but one day on the South Lawn his outsized ego got away from him. As a phalanx of helicopters assembled to transport his entourage, someone asked, "Mr. President, which helicopter is yours?"

"Son, they're all mine," Johnson replied.

Presidents are so shielded from the normal routines of life that they might be forgiven for thinking they are somehow protected from everything. The psychological impact of isolation, despite constant scrutiny, is one for the medical experts to figure out. But it is often humorous to watch them wrestle with their surreal circumstances.

Living in their protective bubble as they do, presidents can be forgiven for losing touch with how normal people live. But often their zeal for personal privacy contributes to their own isolation.

You are not perfect, Mr. President. So don't pretend that you are and hide the bad stuff. If you are still smoking, say so directly, and openly share your struggle with the public.

Protecting your privacy can come at a greater cost than simply revealing what you don't want the public to know. If it is found out -- and it probably will be -- you not only have the fallout from the exposure to deal with, but you will also be accused of deceit.

Open up: The people have a right to know

Presidents usually come into office vowing to conduct the most open administration in history. In the White House pressroom, we tend to snicker at such promises. They are not kept.

The openness or secrecy of an administration depends on the president. It is your job, Mr. President, to set the tone and lay down the rules for how your White House staff views the public's right to the truth.

There are many avenues for a president to get the message out -- through the news media, addresses to the nation and going on the stump. You will regret using those methods to avoid tough questions, distort the truth or try to spin away your problems. It might take a while, but the public will one day catch on.

Although most presidential press secretaries would like to shut the door on reporters, only one, George Stephanopoulos, literally did so. Early in Bill Clinton's administration, he had the door to his staff area closed, apparently not understanding how important this access was to us.

After much griping from the press corps, Stephanopoulos relented. He explained why in his book, "All Too Human."

"Helen Thomas led the charge," Stephanopoulos wrote. "For more than 30 years she had started her day a little before 7 a.m. by planting herself outside the press secretary's office and asking him a question as he walked through the door.

"Now she couldn't do that anymore. With a voice that sounded then like the Wicked Witch of the West's, she went on the attack. ... Helen was letting me know who was really in charge. I may have been working for the new president, but she was part of the institutional presidency. She could wait us out, and she intended to win."

Have courage: Even if it hurts

The theme of your campaign was summed up by the title of one of your books, "The Audacity of Hope." You've given us hope, Mr. President. Now show us the audacity.

In Afghanistan, Mr. President, you risk repeating Lyndon Johnson's disastrous escalation of the Vietnam War after listening too much to the generals. Again, the Pentagon wants more troops for a tricky war, vowing success in Afghanistan if you only agree. That's what the British and the Russians thought before they utterly failed to subdue their foes in Afghanistan's difficult terrain.

Have courage to resist such pleas if your instincts say otherwise, Mr. President. That is why the founders of our nation put a civil servant in charge of the military. You are the decision-maker, not the follower.

Remember, the generals work for you. Think about how Harry Truman once proved the point. He had just fired Gen. Douglas MacArthur for publicly disagreeing with his policy against expanding the Korean War into China.

Truman elaborated on the decision for reporters in his typically blunt fashion:

"I fired him because he wouldn't respect the authority of the president. I didn't fire him because he was a dumb son-of-a-bitch, although he was, but that's not against the law for generals. If it was, half to three-quarters of them would be in jail."

Give us vision: It's your legacy

A good president, wrote 19th century historian Henry Adams, "resembles the commander of a ship at sea. He must have a helm to grasp, a course to steer, a port to seek."

The port you seek, Mr. President, is your vision. Those who take this lightly do so at their peril.

But even the most inspirational vision is just talk if not combined with action.

Now is the time to fill in the blanks, Mr. President. The excitement and newness of your presidency has worn off. Turn your vision into reality. Show us that you can deliver results.

The opinions expressed in this commentary are solely those of Helen Thomas and Craig Crawford.