1. Maintain an assertive posture.

Want to know how to appear more confident? It's all in your posture, says Pachter. "To stand confidently, keep your legs aligned with your shoulders and your feet approximately four to six inches apart. Distribute your weight equally on both legs, keep your shoulders back—but not way back—and turn your body towards others."

When standing, imagine a string pulling your head up toward the sky. Picture a straight line existing from your earlobes through your shoulders, hip and the middle of your ankles.

2. Consider using power poses.

In Amy Cuddy's 2012 TED talk on body language, the social psychologist reveals that just two minutes of various power poses can greatly help make someone feel and appear more confident. In these poses, much of which involves open body positions that takes up space, your body signals to the brain that you're feeling confident, and in turn, the brain produces more testosterone and lowers your cortisol levels, also known as the stress hormone.

In the talk, Cuddy says, “our research has broad implications for people who suffer from feelings of powerlessness and low self-esteem due to their hierarchical rank or lack of resources."

If you're wondering how to look confident, consider practicing some of the poses Cuddy suggests before a big meeting or every day until they feel natural.

3. Watch your hands.

"An important part of mastering body language is knowing what your hands are saying," Pachter writes.

The last thing you want to do is offend someone by jabbing a finger in his or her face. Pointing can seem aggressive, but many people do it without understanding how intimidating it may be to others. Instead, when you're explaining an idea, "point with an open palm, and keep your fingers together," she says.      

4. Pay attention to your face.

Know what your standard face looks like. This is the face that most people see when you're looking at them, listening to them or just not talking in general. Some people's standard faces can be very stern and not communicate what they're feeling on the inside.

"There can be career consequences to having a severe standard facial expression. People may avoid you, think you are mad at them or get defensive around you. These are not good outcomes if you want to connect with people," Pachter says.

What can you do? Pay attention to the comments your friends and colleagues make when you're listening to them. Do they think you're upset because you've furrowed your brow in concentration? If this is the case, try to relax your muscles or smile more often when meeting new people. 

5. Maintain appropriate eye contact.

When you're able to maintain eye contact, you're communicating to others that you're honest, approachable and confident. Those who aren't able to maintain eye contact or are the first to break eye contact signal that they're hiding something, feeling uncomfortable, or projecting a lower-status than or submissiveness to the person they're speaking with.

Just make sure that your eye contact is appropriate and doesn't become too aggressive, making others uncomfortable. In his book The Power of Eye Contact, author Michael Ellsberg says that “in order for eye contact to feel good, one person cannot impose his visual will on another; it is a shared experience."

6. Mirror the body language of others.

If you want to bond with others, consider mirroring their body language to build understanding and acceptance. For instance, if someone is sitting in a certain way, consider sitting in a similar position or mirroring the expressions, movements and other simple mannerisms of the person.

But it's not enough to mimic or copy someone else's body language; you also need to know when it's not appropriate to do so. The success of mirroring comes down to doing it in a way that feels and seems natural, not to imitate or irk those around you.

7. Stop fidgeting.

Whatever it is that you do—jingle coins in your pocket, tap your foot repeatedly on the ground or twirl your hair—stop fidgeting as it betrays a lack of confidence. Sometimes these acts come off as signs of nervousness, which is the last thing you want to project if your aim is to come off as confident. These movements can also take away from the message you're trying to communicate and may distract people from getting to know you. Pay attention to what triggers your fidgeting habits, and attempt to replace those habits when you experience those triggers.

Now that you're aware of the previous tips, the question of how to look confident should be easier to answer. The key is to not let your body language undermine what it is you want to do as a leader. Since a large part of communication comes from body language, which includes posture and facial expressions, take great care in the messages you put out there. Consider using the above tips to help you become more aware of the image you're projecting.