I have a full-on job, two school-age children, and an elderly mother to care for, so I understand that we're all busy; I'm not trying to pile on the guilt. But I'll never forget what my daughter, then four, said one day. We were working on a jigsaw, but I kept nipping to the kitchen to check my phone. When I rejoined her for the third or fourth time, she rightly observed, "Daddy, you're not really here, are you?"

Resilience comes from relationships; children need nurturing. It's not a magical "inner strength" that helps kids through tough times; instead, it's the reliable presence of one, supportive relationship, be it parent, teacher, relative, family friend or healthcare practitioner. My key point is, it's quality, not quantity, that counts. Ten minutes of fully focused attention is better than an hour when your mind is on other things. If you're on your tablet at the dinner table, you're teaching them it's OK to always be distracted. And that they are not important enough for your sole attention.

One-on-one time doesn't have to be time carved out of an already hectic schedule. Make bath-time, car journeys, meals, queues count. Chat, listen, talk about your feelings, encourage them to express theirs. Once these one-to-ones become regular, your children will know they always have a safe space to open up.

I see so many children who are struggling to sleep, waking tired, with dark circles under their eyes. A lack of good-quality sleep is a huge driver for stress: it has a negative effect on memory, concentration, cognitive function, and decision-making.

One of the fastest ways to improve sleep – for all of us – is to limit screen time before bed. The type of blue light emitted by digital devices suppresses production of melatonin, the hormone that signals to the body it's time for sleep. In addition, looking at screens before bed keeps us emotionally wired and stimulated, making it harder for us to switch off.

It's a steely parent who can ban tech completely, and I don't think you need to. But I would urge you to issue a household ban on devices at least an hour before bedtime. Turn off the wifi, if need be. (TV isn't so bad if you need that as a compromise; we tend not to sit as close to the screen.)

Earlier in the evening, insist everyone uses "night-time mode" on their devices, which swaps the blue light for a warmer glow. You can download apps that do this (such as f:lux), too, or buy blue-light-cancelling glasses. It's also worth switching your children's night lights to red ones – red has the least impact on melatonin production. When I did this in my children's rooms, they slept in more than an hour later the next morning.

We all know that regular activity is important, and that most of us, children included, need to do more of it. But what if I told you that, as well as keeping them physically fit, exercise will increase your child's resilience? It actually strengthens the brain.

It's well documented that exercise is on a par with medication when it comes to treating mild to moderate depression and anxiety. This could be because it gets the body used to moving more fluidly in and out of the stress state. The same hormones released when we're stressed (cortisol and adrenaline) are raised temporarily when we exercise. Regular physical activity teaches our stress-response system to recover more efficiently.

It can be a lot of fun to do this together, and I've learned that kids do what they see us doing, not what we tell them to. I'm a big fan of "movement snacking" – short bursts of exercise throughout the day. I'll put on the radio before dinner and we'll all dance around in the kitchen. Or my kids will join me doing squats, star jumps, bear crawls or frog hops. The sillier I look, the more they seem to enjoy it.

Resilience means understanding you can't always have what you want as soon as you want it. It's an important concept to pass on in the age of Amazon Prime, Spotify, Netflix and Uber. Psychology teaches us that people who can accept delayed gratification lead happier, healthier lives. Without the ability to defer pleasure and reward, our kids are losing an important skill for their wellbeing.

One of the best ways to teach it? Playing board games. These require impulse control, turn-taking, and mental flexibility. They exercise the prefrontal cortex, the rational part of the brain involved in decision-making, emotional regulation and, yes, resilience. Board games are also a good way for you to model resilience by being a good loser.

But there are no shortage of other ways to encourage delayed gratification: learning a musical instrument; listening to whole albums instead of skipping from track to track online; mastering a new sport; even watching a TV series together week by week, instead of bingeing in a couple of sittings.

Nutrition has a significant impact on mental health. Good-quality food changes the composition of our gut bugs, which helps send calm signals to the brain. Poor-quality, highly processed food sends stress signals instead. A diverse diet, rich in fibre, will lead to greater diversity in our gut bugs, which in turn will help make us more resilient, and anxiety and depression less likely. Persuading kids to eat more healthily can feel like an uphill battle, though, especially if they're fussy, so this is not about becoming a top chef – just trying a few tricks that can really benefit them emotionally.

I like to challenge the whole family to "eat the alphabet" over 30 days. I think it's a realistic goal to consume 26 different plant foods in a month: A for asparagus, B for banana, C for chickpeas, and so on. It turns healthy eating into a game, and encourages children to try new foods. Turn it into a competition and see who can tick off all the letters first.

Instead of pestering your children with questions such as, "How was school?" and, "What did you do today?", teach them to reframe their day.

The following is a game I learned from a friend, who played it with his daughter over dinner. Everyone must answer three questions:

1. What did someone do today to make you happy?
2. What did you do to make someone else happy?
3. What have you learned today?