Have short hair or be bald
According to studies, men with very short hair or are bald are seen as more confident, dominant and intimidating.
Have V-shaped brows
Women can change their brows to make them angled or v-shaped to look more dominant. Generally, angled features reflect more dominance than circular or round ones.
Studies have shown that smiles make the people around you more comfortable and can in some cases be considered a sign of submission.
Wear dark colors
According to psychologists, dark colors such as black and dark blue can reflect more mystery, which could in turn make a person look dominant.
One study has claimed that men who wear red are considered more threatening to people since red is a color that most people associate with danger.
Don’t dress overly casual
Dressing in overly casual clothes can make a man seem less intimidating. Leather jackets, v-necks and boots can give a threatening impression.
Lock eye contact
Locking eye contact and not shifting your gaze away often can make you look more intimidating. Some people might not like that though.
Standing upright reflects confidence and can communicate dominance. Stand upright with both your feet planted on the ground.
Get a tattoo
Some people might find Tattoos intimidating as they connect them with being a bad boy or a dangerous person. (See What impression do tattoos give?)
Increase your size
Any size increase whether through exercising, the right choice of clothing or high heels (for women) can make the person look more intimidating.
Half-close your eye
If your eyes are wide then they will usually reflect innocence and friendliness. Having your eyes half closed, as if you are responding to sunlight, can make you seem more intimidating.
Unless you have an intimidating voice, speaking less can help you seem intimidating. Speech mistakes and a high pitched voice can make a person seem less intimidating. (See How to have a deep voice?)
Grow facial hair
Facial hair, especially a long beard, can make a man look more intimidating.
10 myths about psychology, debunked by Ben Ambridge | TEDxYouth@Manchester