He says that while any two employees may be 8/10 when it comes to productivity and the quality of work, the one who puts their best face forward and exudes confidence will usually shine.
"How you market and brand yourself in the workplace is extremely important," he says. "The combination of confidence and competence is very powerful."
One of the keys to developing workplace confidence initially is having a supportive team around you. A good manager can help to create such an environment; even if companies are in a state of flux with constant restructuring, good managers can help their staff to remain unified and focused on the future.
The adverse is true of bad managers; even the most competent team will struggle under leaders who micromanage, make bad decisions, or show little respect to their employees. In cases such as this, drawing on external support can be very useful in raising your levels of self-esteem.
"Family, friends and mentors can provide you with a great sounding board," says O'Neil. "It can be hard, but it's important that you keep your 'game face' on when you are in the office. But don't be afraid to ask for help from people outside of work if you are finding your day-to-day working life is challenging."
He says that it is easy to assume you are the only one feeling uncomfortable in the workplace, but feels the reality is often very different. Being aware that others are struggling can help you feel less alone in a challenging environment.
"You will usually find that your co-workers are like ducks -- they seem calm on the service but they are paddling furiously underneath," says O'Neil.
"Try to find people who can help you co-pilot your way through difficulties, develop good outlets for your stress, and don't take negativity into the workplace with you. Such negativity will affect not only you, but also the people around you."
If your workplace is particularly toxic, keeping on top of issues can be taxing and ultimately undermine even the most confident of workers. There are some key signs to look out for when trying to establish whether or not your workplace is sapping your self esteem.
"If you turn up on a Monday and you're feeling two out of ten, and each subsequent day sees this reduce, it's likely that something is wrong," he says. "We all have bad days or weeks at work, but if it's really sapping your energy and leaving you feeling terrible it's important to try to address what is going on."
If you have established that there is really no light at the end of the tunnel when it comes to work, it's useful to plan an exit strategy that will allow you to leave with your confidence intact.
"This is particularly useful in workplaces that are undergoing restructures," says O'Neil. "Getting your CV in order and identifying other places in which you would like to work can really change the way you feel about the situation."
He says that this is likely to also give you an edge over your co-workers -- if the worst happens and you have to face up to redundancy your preparation could mean you are weeks if not months ahead of your colleagues when it comes to job readiness.
While workplace confidence is undoubtedly positive, it's important that this doesn't flip into arrogance. Those with narcissistic or hubristic tendencies can also come across as confident, but this often doesn't translate into good performance.
"Some people talk a great game, but when it comes down to it perform very poorly. They are your classic shysters -- people get caught up in their rhetoric and want to be part of their vision but there is nothing underpinning this," O'Neil explains.
He says that confidence needs to be underpinned by competence; but unfortunately this sometimes doesn't reveal itself to employers until someone is enmeshed in a role.
"Employers are well advised to look carefully at the past performance of people who seem extremely confident and who talk themselves up a lot. Someone who appears very confident may be initially appealing, but it's worthwhile talking to their previous managers about whether or not this confidence is in fact arrogance or narcissism."