There are 168 hours in a week. But it never seems like enough.

If you do the math, we sleep about 56 hours a week (that’s if you get eight hours a night).

Then, of course, there’s work. On average, Americans work about 47 hours a week. But author Laura Vanderkam says for a lot of us, it feels like a lot more.

“Because people can be accessible around the clock with our cell phones and the like, we tend to feel like there’s that demand there,” Vanderkam says. “It’s easy to feel like you’re in work mode even if you’ve only checked e-mail once an hour.”

Vanderkam is author of the book, I Know How She Does It: How Successful Women Make The Most of their Time. In her research, she studied time diaries to figure out exactly how days break down for most people (the U.S. Bureau of Labor Statistics keeps them too, by the way).

Here’s what she’s learned about how we can use our time better:

Take a Break

It’s 4 p.m. You’ve been at the office since 8 a.m. You took a 30 minute lunch, but other than that, you’ve been glued to your desk working on a report due the next morning. Suddenly you find yourself reading random news sites. You’re taking a fake break because your brain needs a real one.

“You didn’t mean to do that,” Vanderkam says. “It’s just that because you were unable to focus anymore, that’s what your brain makes you do. It would've been better to get up and actually take a break and then focus for the rest of the afternoon.”

When Do You Work Best?

We tend to work better at certain times of the day. Some people work better in the morning, others late at night.

If you’re a morning person, congratulations! You’ve got an advantage over the rest of us Vanderkam says.

“The world is set-up to reward [morning people],” she says. “People who are functional at an 8 a.m. meeting are the ones who are going to impress their bosses. Schools start early so students who are good in the morning are the ones who are going to get the good grades. And, that is not fair at all, but it is the way the world works currently.”

So if you work better late at night, see if you can create a schedule that allows you to work then.

“Sometimes you’ll see people are self-employed, particularly in creative fields, and then they can try to maximize their afternoon and evening hours so they don’t have to be at that 8 a.m. meeting,” Vanderkam says. “But if you have family members that can be hard.”

Use Every Second

A woman who kept a time diary in Chicago taught Vanderkam about the value of each minute. The woman took her children to school each day, then had a traffic-clogged commute to work.

They needed to leave by 7:10 a.m. to be on time. But she made sure they were ready by 7 a.m. She spent those ten minutes to play with her children.

“I can really learn from that,” Vanderkam says. “Because I have four small kids. Every bit of potential leisure time or calm time is always fleeting. But just because it’s fleeting doesn’t mean I can’t use it, I can’t notice that it’s happening and enjoy it while it is.”