I'm always trying to figure out ways to keep hold of memories. My one-sentence journal, for instance.

Do I need fifty finger-painted pictures by my toddler, or is one enough to capture this time of life? Mementos work best when they're carefully chosen - and when they don't take up much room!

It's easier to get rid of things when you're giving them to someone who can use them, but don't let this kind intention become a source of clutter itself. I have a friend who has multiple piles all over her house, each lovingly destined for a particular recipient.

Now, the term 'friend' is a little loose. People mock the 'friending' on social media, and say, 'Gosh, no one could have 300 friends!' Well, there are all kinds of friends. Those kinds of 'friends,' and work friends, and childhood friends, and dear friends, and neighborhood friends, and we-walk-our-dogs-at-the-same-time friends, etc.

It's so easy to use tired, shopworn figures of speech. I love using long, fancy words but have learned - mostly from writing my biography of Winston Churchill - that short, strong words work better. I am ever-vigilant against the passive and against jargon, both of which are so insidious.

My writing tends to become very dense, so I have to keep some cushion. Sometimes, words that seem superfluous are actually essential for the overall effect.

One of my most important 'Secrets of Adulthood': Outer order contributes to inner calm.

Don't let yourself fall into 'empty.' Keep cash in the house. Keep gas in your tank. Keep an extra roll of toilet paper squirreled away. Keep your phone charged.

I collect axioms, paradoxes, maxims, teaching stories, proverbs, and aphorisms of all sorts, because I love to see complex ideas distilled into a few words.

One of my key realizations about happiness, and a point oddly under-emphasized by positive psychologists, given its emphasis in popular culture, is that outer order contributes to inner calm. More than it should.

Although we often assume that feelings inspire actions, in fact, actions also inspire feelings. By pushing myself to act happier, I make myself feel happier.

It was my interest in happiness that led me to the subject of habits, and of course, the study of habits is really the study of happiness. Habits are the invisible architecture of everyday life, and a significant element of happiness.

In 'Before and After,' I identify the sixteen strategies that we can use to make or break our habits. Some are quite familiar, such as 'Monitoring,' 'Scheduling,' and 'Convenience.' Some took me a lot of effort to identify, such as 'Thinking,' 'Identity,' and 'Clarity.'

Happiness is a critical factor for work, and work is a critical factor for happiness. In one of those life-isn't-fair results, it turns out that the happy outperform the less happy. Happy people work more hours each week - and they work more in their free time, too.

Like most people, I have several pet subjects - that may or may not be interesting to other people. Don't get me started on happiness, or habits, or children's literature, or Winston Churchill, unless you really want to talk about it.

Whenever I'm trying to decide how to spend my precious time, energy, or money, I ask myself a series of questions. 'Will this broaden or deepen my relationships?' 'Will this contribute to an atmosphere of growth in my life?' 'Is this a way to 'Be Gretchen?' and 'Will this help connect me to my past?'

We can use decision-making to choose the habits we want to form, use willpower to get the habit started, then - and this is the best part - we can allow the extraordinary power of habit to take over. At that point, we're free from the need to decide and the need to use willpower.

Kennedy was president for only 1,037 days, but during his short tenure, he achieved much. At the Cold War's most dangerous hour, he preserved the peace. He improved relations with the Soviet Union and replaced tension over Berlin with a limited test ban treaty.

For one person, organized files might be a crucial tool for creativity; another person finds inspiration in random juxtapositions.

Sometimes, counter-intuitively, it's easier to make a major change than a minor change. When a habit is changing very gradually, we may lose interest, give way under stress, or dismiss the change as insignificant. There's an excitement and an energy that comes from a big transformation, and that helps to create a habit.

People often assume that the same approach will work for everyone, that the same habits will work for everyone, and that everyone has the same aptitude and appetite for forming habits, but from my observation, that's not true.

One thing I wish I could tell my younger self: take photos of everyday life, not special occasions; later, that's what will be interesting to you.

Growing up in Kansas City, I was always neat, the teacher's pet, know-it-all type.

Most people enjoy 'potato-chip news' from time to time - to track a presidential election or the Oscars. However, some are particularly drawn to material that makes them feel shocked, frightened, insecure, or indignant, and that's what potato-chip news often provides.