With the new year underway, you might find your resolutions being put to the test. You're tired and the gym is busy; the weather is awful and a huge bowl of pasta would cheer you up; you can't even think about retiring so why bother with savings?

People love to set goals, but there can be such a big gap between intention and action that resolutions fall by the wayside.

One problem is that people often predict that they will behave better than they actually do. The Daffodil experiment is a great example of this. On one weekend in spring each year, Cornell University sells daffodils to raise money for charity. The students are motivated (it is for a good cause), have easy access to them (the daffodils are on sale everywhere on campus) and they are cheap (they only cost a dollar).When asked how likely they were to buy a daffodil, 83% of undergraduate students said they would buy at least one flower. The reality? Only 43% did.

Clearly good intentions aren't enough.

Research carried in 2015 found that in broken resolutions, 80% of transgressions occurred within three months or less. It sounds depressing, but fear not. Psychology has the answer to help you battle temptation and maintain new habits. Here's why it's so hard to keep resolutions – and what you can do about it.

Maintain motivation

The motivation to start a new behaviour (such as losing weight) may light a spark but it is unlikely to maintain the fire over time. Humans need gratification – as well as long-term ambition – if they are to maintain a new habit.

This idea was explored in the marshmallow experiment. In the 1970s, Stanford researcher Walter Mischel asked three- to five-year olds not eat a marshmallow placed in front of them for 15 minutes. If they could resist, they would get two. For those who could do it, the results were striking: 10 years later, those children who could wait (and so delay gratification) were rated by their parents as being more attentive, verbally fluent, academically and socially competent, and were better able to deal with frustration and stress.

This means you need to break down your long-term goals. Find a motivation that will bring a short-term win, for example, going to a group exercise class that you find fun or setting monthly rather than annual savings goals. 

Self control

Humans are really bad at self-control – if you surround yourself with the thing you are trying to avoid, you are more likely to engage in it. The obvious solution is to remove temptation; if you want to eat healthily, make sure you have nothing unhealthy in the house. You can develop more long-term effective strategies that help you overcome barriers and obstacles, however. How you talk to yourself can make a difference (for example, stopping to take stock and ask yourself questions), as can setting your goals properly (for example, being specific and surrounding yourself with positive people).

Maximise your resources

Look after yourself both physically and psychologically. If you are feeling tired, anxious and frustrated, it is difficult to be your best self.

A great starting point is getting a good night's sleep. An InnerDrive blog, Nine common sleep mistakes, gives you tips on this. You can also try to not put yourself under too much stress avoiding unrealistic expectations. This can be done by steering clear of words such as "always", "never" and "should", and replacing them with "sometimes", "occasionally" and "could". This will reduce anxiety, quell feelings of doubt and boost motivation and confidence.

Create daily habits

New behaviour is most likely to be effective when woven into your daily routine. When it comes to closing the achievement gap, researchers call these low-level affirmation tactics and "subtle" and "stealthy". As with students, if you do not have to think too hard about if you should do it or not, it can become second nature.

This requires you to make small changes that you can embed into your routine. Changing too much too soon is quite a shock to the system, which can seem like a mountain to climb on the days when you don't feel motivated.

Build a team

Having a supportive environment of people who can help you is key. There is an old African proverb which says: "If you want to go fast, go alone. If you want to go far, go together."

A recent study on mental effort found that it is contagious. During the experiment, when conducting separate computer tasks but in pairs, individuals performed better when both partners had to give the same level of mental effort (aka same task difficulty) than when the individual was the only one with a more difficult task. So if you want to work hard, and work well, try and surround yourself with people who do exactly that.

Final thought

These tips don't guarantee that new year resolutions will be kept. Behaviour change is hard. Really hard. By being psychologically smart, however – by maintaining motivation, maximising self-control, looking after yourself, weaving new behaviours into daily habits and having good social support – you give yourself the best chance possible.

This piece is an extended version of a blog which originally ran here.