If you're like most of us, you spend your days wishing for more time. If only you could have an extra hour or two in the day, you think, you could be so much more successful. But time is not our most precious resource--attention is, according to Shelmina Abji, a former IBM vice president who led a team making more than $1 billion in sales. Abji is now a TEDx speaker and author of the new book Show Your Worth: 8 Intentional Strategies for Women to Emerge as Leaders at WorkAnd, she says, a few simple changes to how you spend your workday will help you maximize the precious resource and help you reach your biggest goals.

Why does Abji say attention is so important? If you think about it, the most successful people in the world have exactly the same 24 hours in a day that you do, she explains. "What differentiates our success is how we allocate our attention."

Because we all walk around with mobile devices, we all have information and alerts coming at us all the time, she adds. "If we're not careful, we could be in a meeting--or at dinner with our spouse or children--and our attention is somewhere else. So we are not truly present."

If that happens, you risk losing out. "If you're not truly present, it's very difficult to figure out how you can show up in the best possible way, add value to the situation, and move toward your own success," she says. 

Here's Abji's advice for putting that most precious resource--your attention--to the best possible use.

1. Focus on the present moment.

If a meeting, conversation, or task is important enough to deserve space on your calendar, it's important enough to deserve your undivided attention as well, Abji says. That means setting aside your mobile device and really listening.

It will help, she adds, if you have a desired outcome for every such encounter. That desired outcome might be for you to learn something, to contribute something useful, or both. And you should always strive to leave the best possible impression, which is how you build your personal brand, she adds.

Even if what someone has to say is boring or repetitive, you should still be paying attention, and looking for opportunities to contribute value to the conversation. "Put yourself in their place. If you're speaking and someone's not listening to you, how would that make you feel?" 

2. Stay energized.

It's tough to really be present if you're feeling overwhelmed and exhausted, Abji says. So she recommends creating your own strategy to feel energized throughout your workday. Begin with a morning routine that leaves you feeling energized when you start the day. And then, make sure to take frequent breaks throughout the day, either 5-10 minutes every hour, or 15 minutes every couple of hours. Make sure to build in a little buffer time between meetings or phone calls so you can recharge. "You need to know yourself well enough to know how you can show up fully energized and ready to fully engage," she says. "And then show up like that every single week."

3. Learn how to say no.

As Warren Buffett and others have noted, the more successful you are, the more you have to say no to things. How do you get good at saying no? Begin by having a clear idea of what your highest priorities are, Abji says. "What is the opportunity that, if you achieve it, it will move you closer to your own definition of success? What deserves my attention?" Only things that meet these criteria should make it onto your calendar, she says. 

Your customers' priorities, or your boss's, should be your priorities too, she adds. But if a suggested meeting, conversation, or task doesn't meet these criteria, say no kindly but firmly.

That will allow you to derive the maximum benefit from the things you say yes to. "When you do that, you will be fully present, because you already have an agenda for how you want to show up," she says. "What do you want to get out of it? What's the value you want to create? How do you want to grow?" When you're focused on these questions, she says, "Your mind will not wander into the past or the future or anywhere else."

Bringing that degree of attention to every meeting you attend requires saying no to a lot of other meetings and invitations that don't help you toward your goals, she says. "For many people, including me, it is very difficult. We want to be collaborative. We want to come across as team players. We want to please people and make friends with people. So we will say yes, even when something doesn't move us toward our definition of success. But when you do that, you are not optimizing your performance. In the end, you will lose respect. And you won't be able to bring your best self to anything that you do." That benefits no one--not your customer, not your company, and certainly not you.

Treating your attention like a precious resource, one to be nurtured carefully and spent wisely means you will do outstanding work when it matters most. Try making these small changes, and see what they can do for you.