Got a case of the Mondays... every Monday? Whether you're stuck in a dead-end job or can't seem to move the needle on your new venture, it can be tough to start off your week feeling chipper and empowered when things simply aren't going your way.

Everyone has been there at some point. That's why many top entrepreneurs adopt morning routines that set themselves up for success. Yet some of their routines can take hours. If you've only got a few minutes to spare each morning -- or even less -- than here are a few powerful mantras that can have a huge impact on making the rest of your day meaningful and productive.

1. Today I am thankful for...

Oprah has a gratitude journal. For years, she's written down five things she's grateful for. She claims it's the single most important thing she's ever done. Oprah stresses physically writing these five things down because it consciously forces you to observe what you have to be thankful for.

"If you concentrate on what you have, you'll end up having more -- even if it's just $2," she says in Oprah's LifeClass. And the things can be very simple. One of Oprah's examples? Eating cold melon on a bench in the sun. That's an actual entry from her own gratitude journal on October 12, 1996.

2. I have what it it takes to get through today.

If you're living as good of a life as Oprah, then finding things to be grateful for sounds easy. But what if you received terrible news yesterday or simply woke up on the wrong side of the bed? If negativity creeps in the second you open your eyes, immediately start building yourself up. Remind yourself you've made it here. And you've got what it takes to keep going.

"Thinking things like 'I can't do this,' or 'This isn't fair,' will cause you to feel defeated," says Amy Morin, author of 13 Things Mentally Strong People Don't Do. "If you've made it this far in life, you clearly have some skills, tools, and resources already in place." Morin recommends several more build-yourself-up mantras. Remind yourself that the best you can do is the best you can do. And to put things in perspective, ask yourself if whatever's troubling you will matter five years from now.

3. Today I will accomplish...

Ever surprised to discover it's suddenly 5 p.m. and you haven't gotten a lick of work done?

Instead of reacting to the barrage of emails or fighting fires throughout your day, there's a better way to get a handle on your day. It starts before those emails even start rolling in.

Take a proactive approach first thing in the morning by making a short to-do list of what you absolutely must accomplish today. Keeping it short is key. Cramming too many tasks on your to-do list is setting yourself up to fail. A concise list also forces you to cut out what's not important. It creates division between what's important and what's urgent. And it gives you clear direction on which tasks you will expend energy on today.

If it's impossible to narrow down your to-do list to just a few items, then break it out into mini lists. For example, Shark Tank investor Barbara Corcoran prioritizes things that will make her money and move business forward, FastCompany reports.

While there are plenty of apps or online tools that can help, she prefers the old-fashioned way. "And while I've tried different online to-do lists, I cannot work off of a to-do list that isn't written or typed," Corcoran told FastCompany. "The delete button will never give you the kicks that crossing off tasks will give you."

4. What's my big, ambitious goal for the day?

Your to-do list may contain the tasks you need to plow through today. But don't forget about the big picture. Both Steve Jobs and Benjamin Franklin famously challenged themselves each morning to seize the day with a big-picture question.

In his famous 2005 Stanford commencement speech, Steve Jobs said he looked at himself in the mirror each morning and asked, "If today were the last day of my life, would I want to do what I am about to do today?"

Benjamin Franklin's daily routine started at 5 a.m. Throughout his 3-hour morning routine of rising, washing and contriving the day's business, he reflected on The Question: "What good shall I do today?"

5. My intention for today is...

Yoga instructors often ask you to set an intention at the top of the class. The goal is to pick a word that will help you focus your attention. If your mind wanders, you're supposed to come back to that word. For example, if you've been feeling frustrated with your inflexibility to get into a particular pose, your intention might be "patience." If you're stepping onto your mat after a stressful and busy day and are having trouble slowing down your mind, your word might be "calm."

It's the same approach for setting an intention at the start of your day. Think through what's planned for today. Is there a word or intention that you want to channel throughout your your jam-packed day of meetings? As you go about your day, try to keep this word in mind.