If someone has already made up his or her mind about you it can be very difficult to change, so making sure your body language is working for, rather than against, you is crucial. This applies whether you are asking for a raise, meeting a potential new client, and especially when applying for a new job or role.

Judy Sahay, director with digital media agency Crowd Media HQ says there are plenty of do's and don'ts around body language when it comes to securing new business. “Conducting yourself in a business meeting can be nerve-racking in ordinary circumstances, but is particularly daunting when attempting to make a positive first impression and secure a new client or a raise,” she says.

Here are six do's and don'ts of ensuring your body language works in your favour.

1. Do have a firm handshake. Sahay says a firm handshake makes a great first impression. “It doesn't need to be bruising,” she says. “But by going straight for a stable grip you display confidence and subtle dominance and immediately establish yourself as someone to take seriously.”

2. Do meet someone's eyes. A failure to look someone directly in the eye makes you come across as shifty and untrustworthy. But corporate coach Kyla Tustin says making too much eye contact, early on can scare some people. “It's important to remain aware of the body language of others so that you can gauge how they are responding to you,” she says.

3. Do incorporate subtle hand gestures into your conversation. “Treat a meeting with someone like any other public speaking situation and use your hands to embellish and complement your words,” Sahay says. “But do it without going over the top and making your hands the focus. And if you know you're a fidgeter and the type who toys with their hair or jewellery, then take pains to keep these out of reach. Fussing could very well make you look nervous, distracted, bored, or even rude.”

4. Don't cross your arms. This stance immediately suggests you are on the defensive. “This is a classic sign of disinterest and unfriendliness, and makes you seem closed off and unapproachable,” Sahay says. "Also, keep your hands out of your pocket. This pose denotes a casualness that doesn't work well if you are trying to appear in charge."

5. Don't nod too much. It's difficult to take someone seriously who is constantly nodding. Even if you are in agreement with what's being said, this action is offputting to people who are talking to you.

However, Tustin says it is good to nod occasionally. “It is a great way to show that you are listening, present, understanding and showing empathy in conversations,” she says. “But don't overdo it. Just do it enough to make sure you indicate that you're listening and absorbing everything the other person is saying.”

6. Don't be a blank slate. “While a business meeting is certainly no time to be goofing off, the odd smile or polite laugh here and there helps your potential client feel more at ease and makes you seem more approachable,” Sahay says. “And don't stay perfectly still either. While moving around too much can be distracting, you want to come across as more natural than robotic, so shifting and uncrossing legs occasionally is encouraged.”

And at the end of any interaction, Sahay says you should finish with a handshake and a smile. “While it's extremely important to be perceived as professional and capable, you also want any potential new business client to see you as a warm, likeable person as well.”

Meanwhile, David Penglase of Intentionomics warns against trying to “fake” your body language, despite, he says, some of the recommendations being loosely based on scientific research findings. “What you may achieve is the exact opposite of what you're trying to achieve,” he says. “People get your truth and over time, your intentions, promises, actions and results will either promote you as being trustworthy or expose you as being untrustworthy.”

He adds the “body language movement” is often presented as a panacea for helping people with low levels of people skills to achieve quicker levels of rapport and trust with people. “Often for the purpose of influencing them, persuading them to your way of thinking or to help you achieve a goal you're trying to achieve,” he says. “While there is evidence that supports the messages our body language sends does impact how others perceive us, it is only one element of many that the brain is scanning and reacting to.”