Imagine there’s a large slice of cake in front of you. Do you resist, or give in to temptation, only to regret it seconds later? Studies show that self-control isn’t only useful when it comes to sticking to New Year’s resolutions; it’s essential for a happy and successful life. So how can you improve yours?

Change one thing at a time

Willpower is like a muscle that gets worn out with overuse so, if you’re dieting, it might not be a good idea to try to meditate every day or begin a new fitness regime at the same time, says Gretchen Rubin, author of Better Than Before: Mastering The Habits Of Our Everyday Lives (Penguin, £9.99).

Try willpower-boosting exercises

Self- control can be strengthened by regular practice, says Professor Roy Baumeister, co-author of Willpower: Why Self-Control Is The Secret To Success (Penguin, £8.49). Research suggests that even something as simple as remembering to sit up straight can build your willpower muscle.

 Avoid stress

‘What stress does is deplete willpower, which diminishes your ability to control those emotions,’ says Dr Baumeister. That’s why you’re more likely to open a bottle of wine after a tough day at work, despite having vowed not to drink until Saturday.

Connect to your future self, recommends Kelly McGonigal, author of The Willpower Instinct (Avery, £17). ‘Imagine the life you’d like to have, and the person you want to be, then write a letter from your future self to your present self, expressing gratitude for having the courage to make the changes,’ she says.

Forgive yourself for setbacks

You’ve heard it before, but if you beat yourself up, or decide the day is ruined, you’re much more likely to fall off the wagon completely. Being compassionate allows you to connect with the part of yourself that wants to make the change, says McGonigal.