I turned 75 the other day. There’s something, isn’t there, about reaching an age with a nought or a five at the end of it? It’s a landmark and makes us think.

As you know, I’m passionate about us all doing our best to age positively so, not surprisingly, much of my thinking has been about what we need to do to stay as young as possible for as long as we can. Here are the components I’ve come to believe are the most vital.

Maximising happiness
Being happy feels good. More than that, research shows that happier people tend to live longer, stay fitter, enjoy good mental health and have plenty of energy. Undoubtedly though, being happy is more of an effort for some than others.

Many individuals are born naturally optimistic and contented. Others are less lucky. But through my decades working as a psychotherapist, I realised that every single one of us can improve our happiness levels.

Around 1998, I devised a plan for my patients. It changed a lot of people’s attitudes, including mine. The plan was simply to train ourselves to notice when we’re happy.

And all it entailed was to list five happy moments daily. Also, instead of ending a day by dwelling on what went wrong, I suggested we should all remember what had gone right as well as anything that had made us smile. I’ve been doing this myself ever since, and it works for me.

Get Active
I didn’t come from a family who played sports or went for walks.

And as a child, I was the girl no one wanted in their rounders team, so I grew up believing I was hopeless in that department and avoided all physical activity.

In fact, I was over 40 before I had a go at tennis, which I enjoyed watching, and discovered that if you play on a regular basis, you start to get better at it.

This was a revelation. So, my husband and I began to play several times a week. And through his influence – he was very fit – I became much more active.

But the big breakthrough came when I took my first ballet class at 63.

Now, obviously starting so very late meant I was never going to be able to get my leg up behind my ear or anything ambitious like that, but I loved it so much, and 12 years later, I still do.

It helps my posture and balance, but most importantly of all, my brain is sharper. There’s nothing like following spoken instructions and transforming them into movement for getting those little grey cells working.

Taking up ballet literally changed my body and mind.

And interestingly, once I got into it, I found myself eager to sample other activities that would benefit me, and added yoga, Pilates and lots of walking in the countryside into the mix. Nowadays, people perceive me as an active and fit person. Not bad for someone who was once a confirmed couch potato.

Friends have always been a major cornerstone of my life, but they are even more crucial to me since I’ve been on my own. I know plenty of other widowed and divorced people feel the same.

What I recognise as I age is how essential it is to seize any opportunity you can to make new friends. Why? Because life keeps changing. And sometimes people close to you grow ill or die or just age differently from you, and you lose what you had in common.

My newer pals are mostly drawn from those who share my personal passions. I’ve lost count of those forged through dance, but it’s well over a dozen. Also, joining the committee of Norwich Chamber Music increased my social network no end, as has singing in the wonderful Eye Bach Choir.

If it’s been a while since you’ve made new mates, do put yourself out more to speak to people you don’t know, and consider joining an organisation you’re interested in, because when you do that, you’ll always find like-minded men and women to talk to – and these are potential friends.

Be in touch with your younger self
One of my all-time heroes is veteran American psychiatrist Irvin Yalom. About 15 years ago, when he was the age I am now, he wrote an article in which he said: ‘The past is ever more with me.’ And he discussed his new need to be in touch with his younger self.

I notice this in myself now. For example, I was a keen pianist as a child, but I barely touched the instrument for decades while my career took over.

Now, I play and practise most days – and it’s marvellously rewarding. Also, I’ve just been on a birthday tour to meet up with my Scottish cousins; these are the people who were my playmates when I was small. It was very grounding and fun to be with them again.

And it felt important, though I’m not entirely sure why. Perhaps I’ll have worked it out by the time I’m 80!