Here's the single best way to get a powerful person to like you

Whether you're interviewing with an exec for your dream job or trying to impress your boss, getting powerful people to like you - Machiavellian as it may sound - is an important step toward getting what you want.

While this may seem easier said than done, Columbia University professor Heidi Grant Halvorson explains in her book, "No One Understands You And What To Do About It, the key is proving your instrumentality.

"Instrumentality isn't about being nice - it's about being useful," she writes.

To be seen for who you really are, proving your usefulness is really all that matters, Halvorson explains, pointing to research from the University of Southern California and the University of Colorado. Studies found that powerful people will perceive you more accurately when they feel it's in their self-interest because they're more likely to use their attention strategically.

"In fairness, powerful people tend to be powerful because they have a lot of responsibilities and a whole lot going on," Halvorson reasons. "You have to be worth taking time and energy for, and powerful people have no reason to believe you are unless you give it to them."

To prove the potential return on their time and mental investment, here are a few steps you can take:

1. Understand what the powerful person needs and wants.

Ask yourself: "What are her targets and goals?" "Where does she need the most help?" "Where is she falling behind the most?" Then contemplate how you can help ease these burdens.

In the case of impressing your supervisor, "by prioritizing your own tasks in such a way that they provide assistance to your boss where he or she needs it most, you can dramatically increase your perceived usefulness," Halvorson writes.

2. Go above and beyond.

The most obvious way to be instrumental is to do everything that's asked of you, but most times anticipating a powerful person's needs takes you many steps further.

The most useful research assistant in Halvorson's eyes was someone who had documents ready before Halvorson asked for them and took over thankless and frustrating tasks without being asked. "When she left my lab and moved on to graduate school, I was depressed for a week. That's instrumentality."

3. Don't just list your good qualities.

Powerful people don't care about your list of good qualities, Halvorson writes. They care about your goals and how they align with theirs.

Be prepared to answer: "What are my goals?" "Do they align with yours?" and "How can you be instrumental in reaching them?"