At the end of every year, it's a great idea to look back on the previous 12 months and reflect. Think about what opportunities you missed that you should have taken, how you could have done better, and what changes you would make if you could do it all over again.

It's been said that people who don't learn from history are doomed to repeat it. That's why it's especially important to learn from your own history so that you don't make the same unforced errors over and over again.

Here are the biggest mistakes you (probably) made in 2016.

1. Not Focusing on What You Are Grateful for Every Day

Do you have an attitude of gratitude? If not, then you're already setting yourself back.

Make this New Year's resolution: that you'll wake up every morning and think about what you're grateful for. It will change your whole outlook, make you a better person, and almost certainly lead you to become a more effective team player.

Fortunately, you don't have to look far to find reasons to be grateful. Usually, just a quick scan of the daily headlines about events going on around the world should make you sit up and think to yourself: "Boy, I'm glad I'm not going through that!"

Also, think about what you do have: family, freedom, and the ability to earn a buck in a competitive, but even, playing field. That alone should make you happy.

2. Not Telling People How Important They Are

Even if you're an entrepreneur, it's not likely that you're going it alone. You're working with a team of people.

When was the last time you told them (all of them) how great they are?

If you can't think of an answer immediately, then it's been too long. Get thee to a boardroom and let your people know they're appreciated and respected.

People on your team shouldn't wonder what you think of them. They should know, because you follow Dale Carnegie's advice about dispensing praise and compliments generously.

3. Poorly Managing Your Time

"You can ask me for anything you like, except time."

Those were the words of Napoleon Bonaparte. And for good reason: time is one commodity that you can't get back once you lose.

Think about it: if you lose money, you can earn more money and get it back. The same can't be said of time.

That's why you should go out of your way to manage your time properly. Sadly, too many business leaders fail to practice good time management.

Look back over the past year. Have you organized meetings that really don't matter? Have you performed routine tasks that are best left delegated to someone else? Have you jumped around from email to instant messaging to calls with very little to no focus at all?

If so, then make 2017 the year that you practice better time management. If you're getting some vacation during the holidays, use that time wisely by reading a few good books about time management. Personally, I read one book on time management and it improve my productivity 10 fold.

4. Not Having Clear Goals

It's astonishing how many managers still fail at following the basic principles of Business 101. One of those principles: set clear goals and follow a plan to reach them.

Look back over the past year. Did you find yourself shooting in the dark on more than occasion?

Specifically, look at where you failed over the past 12 months. Don't be surprised if those failures are associated with projects that didn't even have goals.

Virtually every study that's been done on the subject shows that people who set goals tend to achieve more than those who don't. That's true even if the goal-setters don't reach their goals.

Make 2017 the year that you put more of an emphasis on goal-setting if you didn't do so in 2016.

For my own company, I enjoy getting ideas from the entire company and organizing them into a 6 month plan. As Ken Blanchard says, "None of us is as smart as all of us."

5. Not Becoming a Digital Influencer in Your Space

Why aren't people flocking to your website and buying your product or service?

Maybe it's because they don't view you as an authority in your niche.

If that's true, then you have nobody to blame but yourself.

Also if that's true: change.

Make 2017 the year that you market yourself online as someone who's an expert in your field. Engage with key influencers online, write e-books, guest-post on blogs of non-competitors, show off your knowledge in a webinar, and do whatever else you think is necessary to convince others that you know your stuff.

This strategy has landed our company the number one spot in the industry. It can do the same for you. I am so passionate about this online marketing strategy I wrote a book about it.

6. Spending Important Company Funds on Wasted Initiatives

Look back over the past year (maybe with your accountant) and review your unnecessary expenses.

Think about why you spent that money, what frame of mind you were in at the time, and how you can avoid wasting business funds in the future.

If you're pouring cash into advertising that doesn't deliver, employees that you like but aren't performing up to expectations, and/or vendors that you know are too expensive, then maybe it's time to make some changes.

Here is to next year! Best of luck to all.