(CNN) Most of us make to-do lists to keep track of all the things we need to tackle around the house, to keep our families running and to stay on top of tasks at work.
But those lists can get unwieldy. If you often find it hard to check everything off your list despite the best of intentions, welcome to the club.
Ayelet Fishbach, professor at the University of Chicago's Booth School of Business, has been studying the science of motivation for her entire career, and she knows just what it takes to achieve more.
Fishbach is the past president of the Society for the Science of Motivation, and in her debut book, "Get It Done: Surprising Lessons From the Science of Motivation," Fishbach provides a framework grounded in decades of research that can help you finally get through your weekly to-do lists.
This interview has been edited for length and clarity.
Katy Milkman: Are to-do lists actually useful?
Ayelet Fishbach: To-do lists are useful when they help you offload the mental effort of memorizing your list and negotiating priorities. Also, they're useful whenever completing one item motivates you to attend to the next one, therefore escalating motivation.
These lists are less useful when they cost you your flexibility. You might pursue some activities only because they're on the list, even though they're low priority and completing them won't make you happy.
In his research, University of Virginia professor Leidy Klotz has found that it's often more important to subtract, that is remove items from your list, than add new ones. Your weekend might be more restful if you skipped the zoo or the mall.
Milkman: If I have a handful of big goals to accomplish each week around the house, what's the best tip you can offer me for getting them done?
Fishbach: Consider my four-ingredient recipe:
1. Set the goal right. You want to set goals that are intrinsically motivating. An approach or "do" goal is better than an avoidance or "do not" goal. "Attend a morning Pilates class" is better than "don't oversleep."
2. Monitor progress and switch your focus in the middle of your to-do list. Look back at how much you've accomplished up to the midpoint and look ahead at what you still need to do beyond the midpoint.
3. Your goals should balance -- rather than undermine -- each other. Any specific goal should fit with everything else you set to do. If you plan to eat more healthily, cross out that trip to the ice-cream shop.
4. Seek social support. You should have people around you who want you to succeed and might give you a hand when you need the extra help.
Milkman: Why is it that I often feel demoralized when I'm halfway through a long to-do list? And what can I do to stay motivated?
Fishbach: It's the middle problem. Most of us feel less motivated to do work, and do it right, in the middle of goal pursuit. You experience fast progress at the beginning and end. Your first and last actions also feel special -- you celebrate starting and ending something. In the middle, you lose steam and your motivation.
When Rima Touré-Tillery (associate professor of marketing at Northwestern University's Kellogg School of Management) and I asked people to cut out a series of pointy shapes drawn on a piece of paper, we found that they literally cut corners in the middle of a task. They were not paying sufficient attention to their work.
The solution -- keep middles short. Instead of a monthly exercise goal, set a weekly exercise goal and instead of an annual professional goal, set a monthly goal for what you want to achieve at work.
Milkman: When a to-do list gets unwieldy, do you have advice on how to prioritize tasks so something will get done?
Fishbach: You want to make sure that the high-priority items on your list aren't getting neglected.
I recommend using three categories:
1. Tasks that are critical for meeting your duties and promoting your aspirations. They're at the top of your list.
2. Tasks that advance these objectives but aren't critical for either a duty or an aspiration. They come second.
3. Everything else.
So, for me, helping my 10-year-old son practice his violin comes before gardening. Shopping for new professional clothes comes last, so it's often postponed.
Milkman: What are common misconceptions about getting things done that people should abandon?
Fishbach: First is the common belief that whether you're successful depends on who you are as a person. It's not just about you. Success depends on your circumstances just as much and often more so. In the right place and time, and with the right people, you can achieve great things. Psychologists refer to this misconception as the "fundamental attribution error." We tend to look in the wrong direction when considering what enables success.
The second misconception is your lack of empathy for future you. You might believe that future you will do only what's important for them, but that futuristic person, like your present self, will be pulled toward what feels good in the moment.
Milkman: What's a little-known strategy for getting things done that more people should employ?
Fishbach: Consider the temptations and obstacles that will hinder your future success. We find that when you anticipate a problem in advance, you're mentally ready to fight it off when you encounter it. When Ying Zhang (professor of marketing at Peking University's Guanghua School of Management) and I asked students to reflect on the social, fun activities that would stand in the way of completing their coursework, they set more time aside for completing that work.
Knowing about a problem in advance allows you to mentally prepare to tackle it. Think about preparing to lift a heavy piece of furniture. If you correctly anticipate its weight, you'll be ready to approach it with the right level of physical effort. And when you know the situation is going to be tense, you recruit your calm energy and don't lose your temper when the people around you raise their voices.