The key to a successful new year resolution is to keep it achievable and simple.
And don't give up just because of one or two setbacks, says psychiatrist Gordon Parker.
"Find your incentive and play to it," says the University of NSW professor.
It could be betting lots of money with several people that you can stop smoking, he says.
"The other principle is not to worry about the occasional failure along the road.
"Rather see it as a blip.
"Inch your way towards Bethlehem rather than driving onwards with a mission-impossible target."
Going for a GP checkup is a small step that could make a big difference, says Cancer Council Australia CEO, Professor Ian Olver.
Other achievable aims are to be more careful about sun protection or ensuring that you are up to date with your cancer screening.
People could eat more vegetables or decide to use the stairs at work, says Lauren McGuckin, an accredited practising dietitian.
Health is holistic, says Ms McGuckin, a spokesperson for the Dietitians Association of Australia.
"It's more than just diet, physical activity and perfect medical tests. It's also about mental wellbeing. Set small, realistic goals."
She says it is important to eat a wide variety of vegetables. "At least five servings a day."
Oily fish such as salmon, sardines and tuna are an exceptional source of omega 3 fatty acids, she says. And the goal is two servings a week.
Foods rich in unsaturated fats such as nuts, seeds and avocado are also essential for most people.
But there's no magic bullet in diet fads, says accredited dietitian Kate Gudorf.
"A healthy diet is a balanced diet and includes foods from all the core food groups."
Absolute avoidance of any food group is a bad idea.
"Some people believe the myth that they should avoid bread, pasta or rice.
"Certain types of whole grain or wholemeal breads, pasta and brown or basmati rice have a moderate or low GI and provide fibre and B vitamins and energy to fuel us through our day."
Berries are also good, she says.
"Blueberries, strawberries and blackberries are potent sources of antioxidants and vitamin C. They also contain very few kilojoules per serve and taste delicious stirred into muesli or yoghurt or on their own for dessert or a snack."
People should aim for two to three serves of dairy a day, she says.
One of these could be yoghurt.
"It tastes delicious, makes a filling snack or dessert, and is a good source of protein, calcium, vitamin D, riboflavin and zinc. Some also contain beneficial bacteria called probiotics."
Another practising dietitian, Kate Landau, says people should work out what is important to them, and then set up an action plan.
"Understanding your individual drivers and why it is you want a particular outcome will enhance your commitment and could result in more success."
People should work out what they eat and drink and decide if it is more than they need, says the Heart Foundation's Dr Robert Grenfell.
Keeping a food diary for a week is a good idea, he says.
He also wants Australians to get active.
"Thirty minutes of activity on most or all days of the week is great for your general health and wellbeing.
"Walking is a great way to do this. Build a walk into your day by walking to work or public transport."
"It's easier to start your active routine in summer and head into 2014 having already developed a healthier habit."