If you’re sometimes frustrated about how little you accomplish during your work day, you’re not alone. Research indicates that only 26% of people often leave the office having accomplished the tasks they set out to do. It’s common to feel as if you’ve been busy but haven’t done anything important. Of course, life isn’t about being a productivity robot in which every second is optimized. But most of us do want to feel well-organized and efficient in pursuing key goals and solving critical problems. A good first step is to understand the mental mistakes that typically prevent us from focusing on and finishing meaningful work.  Here are [the first two of] five common ones:

1. You overestimate how much focused time you have in a typical day.

Long-term creative projects, strategic thinking, and skill- and relationship-building require big blocks of concentrated attention. It’s easy to optimistically think you’ve got all day, or even several hours, for that type of work and subsequently plan your priorities based on that assumption. However, for many of us, meetings, email, Slack, phone calls, and “quick questions” take up a considerable portion of our time in the office. Aggregated data from the time-tracking app RescueTime suggests that people have as little as one hour and 12 minutes of uninterrupted time in their day.

If you acknowledge the limited time you’ll have for focused work, you can more ruthlessly select your absolute top priority and protect yourself from distractions for certain periods. When you do have 60 to 90 minutes available, try to focus on your bigger-picture goals (as tempting as it might be to focus on more time-sensitive routine work). Remember, too, that even those complex and important projects usually have some admin tasks associated with them (e.g., hunting down a reference when writing a book) that don’t require as much focus or creativity. As a workaround for having limited time for the harder work, identify those to-dos and slot them into that spare 15 minutes you have between meetings or those longer free periods during which you suspect there will be interruptions.

2. You overlook proven, sustainable methods that seem too boring or too simple.

If you consume a lot of productivity self-help material, you’re probably familiar with many core concepts from cognitive-behavioral psychology. For instance, if you form “implementation intentions” you’re more likely to follow through. This involves planning when and where you’ll do a task and how you’ll overcome obstacles you’ll encounter. Likewise, you might’ve previously read about how shrinking the number of decisions you make in a day will reduce your mental fatigue and improve your willpower. And, you might know that when you make any task easier, for example by ensuring you have the needed materials on hand, you’re more likely to begin. However, once we’ve heard these principles, we often write them off as “old news” even when we haven’t fully implemented them or tried them at all.

For each of your important projects, have your next action defined and everything you need to complete it handy and ready to go. For instance, if you want to video yourself rehearsing a big speech, set up the space you plan to use, do a test recording for a minute, and make sure you have enough free space on your recording device. If you remove these types of practical barriers to getting started, they won’t eat into your focused time.

If you like to see yourself as a special or unique individual, you might find that simple solutions don’t sit well with that, since you don’t like to see yourself as being like everyone else. This is a trap. Make sure you’re employing boring, but easy and proven-to-work, strategies in all the ways you could be. Get better at creatively applying simple ideas rather than searching for complex ones.