When you're tasked with leading a new team (either a team that is completely new or one that is just new to you) making a  first impression is crucial. You want to show strength and reassure your team that your leadership will be strong, fair and trustworthy.

If you're new to a team, you need to establish trust right away. Here are four ways new leaders can instill trust with teams, backed by a little bit of science.

1. Display honest and ethical behavior immediately.

Strong ethics came out on top of a study performed by organizational scientist Dr. Sunni Giles where she asked 195 global leaders what the top 10 leadership competencies are.

Every leader when heading up a new team should start by demonstrating honesty and ethical behavior to their new team. Now, this is a little tricky to do because ethical dilemmas (hopefully) don't pop up all that often and not lying to people isn't something most people really take note of on a day-to-day basis as showing strong leadership.

One thing you can do is talk about your commitment to maintaining good ethics and how much you value honesty in your team. This should make a good impression and displaying ethical and honest behavior throughout your tenure will reinforce it.  

2. Have some fun at work.

A Bell Leadership Institute study found that when 2,700 employees were asked over a two-year period about the strength and weaknesses of their senior colleagues and leaders, the phrases "sense of humor" and "work ethic" were mentioned twice as often as other phrases. The study found that good leaders used humor effectively to spark people's enthusiasm, boost productivity, bring teams together or promote glass-half-full thinking during a negative situation. 

And while humor is obviously a great tool, like any other tool, it's how you use it that really matters. Poor leaders also used humor, but very differently. They used it to show off, distract people from tasks and cut people down with sarcasm.

Humor is one of those things that you have to be cautious with. A joke that leaves one person in stitches will offend another. It's a good idea to introduce yourself to your new team with a joke or two to let them know you like to have a little bit of fun at work, but it's best to keep your humor light and middle-of-the-road and never use it in a negative way. 

3. Find out what individuals on your team need and provide it for them.

When the University of Illinois at Chicago College of Business Administration studied nearly 1,000 employees in 71 different locations, they found that when leaders act as servants to their employees, the entire business prospers.

In this specific study, businesses run by leaders who act as servants to their teams enjoy 6 percent better job performance, 8 percent increase in customer service and 50 percent increase in employee retention compared to businesses run by people who were not classified as servant leaders.

This improvement across the board is because servant leadership -- where you focus more on serving your team and what you can do to make their lives better -- is contagious. It is one of the fastest way to change a team culture. Employees see their leaders as role models, and when they start to mimic the servant leadership qualities, the culture changes and results kick in rapidly down the line to customers and clients.

When you're new to a team, you can display this servant leadership style by asking them what they need and taking steps to provide that. These will likely be big-ticket items that will take some time to organize like childcare at work or increased training opportunities. In the meantime, as a small gesture, you could be the one to bring the donuts and coffee to the meeting.

4. Organize a socially responsible activity.

Gallup conducted several polls about leadership that encompassed 10,000 respondents. The company wanted to know what good leaders contributed to respondents' lives. The organization found that people identified four main areas good leaders excel in. Trust, compassion, stability and hope were elements that people identified with good leaders.

One thing new leaders can do that shows all four of these elements in one fell swoop is to organize some kind of charitable event the team can not only contribute to, but participate in. It shows that leaders aren't out for their own gain, which instills trust, and is an obvious way to show compassion. Only leaders who are interested in long-term commitment would organize a charitable event. Along with giving the recipients of the charitable offering hope, you also give hope to your team that they have a good leader at the helm.

From grand to small, gestures that instill trust in new teams will get everyone started off on the right foot.