You've probably heard the saying that 20 percent of your activities account for 80 percent of your success. This means that 80 percent of your activities are of at least low value, if not a complete waste of time. If you want to improve your success, you have two choices--find more time in your day or eliminate those time-wasting activities.

The problem is that a lot of those time-wasting activities have become habits--things you do without thinking. Habits can be difficult to change, but it is possible to replace them with new behaviors. When you replace bad habits with activities that focus on that worthwhile 20 percent, you'll find yourself much more successful in the same amount of--or perhaps even less--time per week.

Here are seven time-wasting habits to cut out of your life for good.

1. Checking email constantly.

In 2013, a whopping 32 percent of U.S. employees reported that they replied to emails within 15 minutes of receiving them. An additional 23 percent responded within 30 minutes. But is faster actually better? Constantly checking email costs us a ton of valuable time, but it is something that can controlled. Create a new habit of turning off your email program and notifications while you work on an important project, or come up with a system to check your new messages only twice a day. You'll save time and get much more done.

2. Waiting for things to be perfect.

It's an unfortunate reality that perfectionism can paralyze you. Instead of doing tasks efficiently, you end up wasting a tremendous amount of time trying to perfect things that should simply be sent on to the next phase. Spending a large amount of time perfecting a task could actually be a sign of procrastinating instead of taking next steps. Instead, crush this time-wasting habit and work until it's "good" before moving forward.

3. Multitasking.

Multitasking has become a bad habit for many Americans, but in reality it makes you less productive. Your brain can focus on only one thing at a time, and constantly switching tasks actually retrains your brain to not really focus at all. If you find yourself toggling between tasks and can't settle on one thing, understand that you're hurting your performance and wasting time. Instead, focus on one task for a specific period of time before moving on to the next one.

4. Inviting interruptions.

Are you working in an environment prone to distractions? One study showed that workers get interrupted every 11 minutes. No wonder we don't get anything done! Think about how many habitual things you do every day that actually invite people to interrupt you, from sending a quick text to checking your email when trying to focus on something else.

Reducing these behaviors will help you keep focused and learn to eliminate distractions. Try blocking out work time on your calendar and marking it as "busy," shutting your door if you have one, silencing your cell phone, and letting others know you will talk to them at another time.

5. Being disorganized.

There are many different ways to organize that don't include a tidy desk. Zappos CEO Tony Hsieh loves a messy desk, while others prefer using filing cabinets. Regardless, a habit of working in disorganized chaos is also a major time waster. Constantly losing important papers, repeatedly asking for key information, and forgetting to complete a task until the last minute are all unnecessary time spenders. Instead, experiment with organizational habits that work for you and use them consistently.

6. Failing to delegate.

Many people insist on doing everything themselves, but refusing to relinquish control can actually backfire. It's a waste of your time to do things that you aren't the best at. Instead, delegate these tasks to others--either others on your team, an assistant, or a virtual assistant--and focus on responsibilities and projects that are within your zone of expertise. Look to eliminate minor tasks like screening emails or research or passing off duties that just don't suit your talents from your schedule.

7. Never saying no.

Failing to say no when it means focusing on time-sucking activities comes at the expense of your core projects. Whether you need to say no to additional work assignments or unproductive personal engagements, it's important to set firm boundaries. Focus on getting your vital projects completed during work hours while surrendering to renewing and refreshing during your personal time. There are plenty of easy and effective ways to give a powerful no without alienating your personal and professional network.