It's tempting for new executives to act like they have all the answers, but often, acknowledging when you don't know the answer and showing humility garners more respect than acting like you know it all, according to H. Irving Grousbeck, an adjunct professor of management at Stanford Graduate School of Business.

Infographic: 7 must-have conversations between managers and employees

Grousbeck offered that piece of advice as part of a recent speech to executives, which Bill Snyder summarizes for "Insights" by Stanford Business. Here are the three main points that Grousbeck covered in his speech.

1. It's OK to say, 'I don't know.'

According to Grousbeck, when an employee comes to a manager seeking an answer that he or she doesn't have, it's tempting for the executive to take a guess. 

"You may be tempted to bluff. Don't," Grousbeck said. "If you bluff an answer, you may be wrong, and that will damage your credibility and your authenticity.

Paraphrasing Grousbeck, Snyder writes that it's important to remember top performers "don't leave companies, they leave bosses."

As a manager, you should be patient, kind, and listen to your employees, Grousbeck said. Specifically, Grousbeck advised managers to show "you care about each individual you interact with, not just about the work that he or she produces." For example, managers can make time to stop at a direct report's office with no agenda other than to say, "Thank you for your great work and your contributions to our culture," Snyder writes.

As Grousbeck said, "Money and stock are in finite supply, while praise and thanks are in abundance and can be even more powerful."

2. Be both a teacher and intervenor.

As a manager, you should be both a teacher and an intervenor, Grousbeck said. An intervenor, for example, will calmly speak with a direct report who was rude to a coworker, or will set clear limits on things like gifts salespeople can give to clients.

As a teacher, the manager should work in tandem with direct reports when solving problems and avoid the phrase "I need you to," favoring instead using the word "we" and a the phrase "could you please," Snyder writes.

3. Know who to hire (and fire).

Along with learning humility, another key lesson for new executives is to learn to focus on retaining top performers and getting rid of poor ones.

"Start by hiring ahead of the curve," Grousbeck recommended. That means executives should identify the best performers and bring them on early, Snyder writes.

But that also means taking a close look at the performance of current employees. "There are few things more demotivating to top-tier employees than seeing mediocre players holding down key roles," Grousbeck said.

While firing isn't pleasant, avoiding that task shouldn't come at the expense of the company's performance, Grousbeck said. "We get off track when we make decisions to accommodate nonperforming individuals we like at the expense of the company's interests," he said.

That said, Grousbeck cautioned that managers shouldn't be quick to fire. They should first work with underperforming employees to improve their performance, but if there is no improvement after two to three months, those employees need to be let go (Snyder, "Insights," Stanford School of Business, 12/13/19).