Elizabeth Grace Saunders is founder and CEO of Real Life E, a time coaching and training company, and the author of "The 3 Secrets to Effective Time Investment: How to Achieve More Success With Less Stress" and "How to Invest Your Time Like Money."

As a time coach and trainer who has worked with clients on six continents and the author of How to Invest Your Time Like Money, I have an insider perspective on what holds people back from their time management goals and what shifts can take them from ordinary to extraordinary. I've discovered that the most effective time managers tend to share the following seven core beliefs.

1. Time should be invested, not managed.

Ordinary time managers try to fit everything into their calendars and make it all work through sleeping less and working more. They focus on efficiency over effectiveness and feel unsatisfied, even when they've accomplished a great deal, because they never get everything done.

Extraordinary time managers invest their time like money. They realize that they can't--and wouldn't want to--put time into every opportunity that comes their way. Instead they focus on reserving their time for their most important priorities, and they feel comfortable letting most opportunities go.

2. Overwhelm is a choice, not a given.

Ordinary time managers see stress and overwhelm as an inevitability on the path to success. Because they don't question this assumption, they tend to blame other people or their situation for their time management challenges. They frequently miss opportunities to be more effective.

Extraordinary time managers realize that their choices determine whether or not they end up stressed and overwhelmed. They take ownership of their commitments, negotiate expectations, set boundaries, and if necessary, leave situations that don't work for them.

3. Saying "No" leads to accomplishing more, not less.

Ordinary time managers worry that if they don't say "Yes" to everything, they aren't doing enough. They overcommit and then either don't follow through, or end up sacrificing other important priorities--like sleep and exercise--to get things done.

Extraordinary time managers know that saying "No" to anything that isn't a great investment of their time gives them a greater ability to accomplish what is. They achieve their most important goals on time and take care of themselves mentally, physically, and emotionally.

4. Knowing the extent of commitments is freeing, not constraining.

Ordinary time managers resist having comprehensive task and project lists because they don't want to know how many items they've committed to doing. They also avoid planning out their activities because they would then see how little free time they had--or even that they were in time debt, meaning they've committed to more than they have time to do.

Extraordinary time managers want to have comprehensive lists of their projects and tasks so they have a complete view of their commitments. This equips them to make informed choices about what's most important now and to confidently know that they're doing the right activities at the right time. A clear sense of the extent of their commitments also frees them to say "No" or "Not Now" to items that aren't their highest priorities, because they know they don't have the free time available.

5. Routines are flexible, not rigid.

Ordinary time managers think routines must happen in a certain way at a certain time or they're useless. They tend to completely abandon a routine instead of modifying or adjusting it to suit the current reality.

Extraordinary time managers understand that routines can be modified, adapted, and adjusted. Instead of abandoning a routine when one step doesn't go as planned, they make adjustments so they can still accomplish the goal behind the routine, such as getting enough sleep, exercising, or planning.

6. Perfectionism is a hindrance, not a help.

Ordinary time managers approach every task in the same manner. They see how they do every activity as a reflection of who they are. That means if they see themselves as a high-achieving perfectionist, everything they do must be completed to perfection.

Extraordinary time managers strategically decide the value of investing time in different tasks. They understand that where they invest the majority of their time and effort is a reflection of who they are. That means that they choose to give their very best to what's most important. They choose to not do or do imperfectly the items that aren't as important.

7. Time management is the means, not the end.

Ordinary time managers focus on time management systems. They get overly concerned about whether or not they have the latest and greatest in tools. They also tend to obsess about getting everything on their to-do list done, being precisely on time, and getting to inbox zero.

Extraordinary time managers have a radical focus on getting the most important priorities accomplished. They want to know what's most important and get it done on time and to the appropriate level of quality. They don't get too stressed about leaving some task incomplete, being a few minutes late, or neglecting some emails. They know that in the end, focusing on the highest investments of their time will lead to the best results.

As you take your time management in 2015 from ordinary to extraordinary, what core beliefs will you shift?