I was eleven, had just started secondary school and was getting used to the giddy notion of having my own set of keys and letting myself into our fifteenth-floor flat. One day my mum arrived home shortly after me, beaming with pride. An older lady neighbour had just told her I was "an absolute angel", and many other neighbours apparently agreed.

What had I done that was so special? Foiled a bag-snatching thief or something equally dramatic and impressive? Nope, my angelic powers were much more everyday… When I was in the lift with that lady - or any of my neighbours - I smiled. I said hello. I chatted a little bit.

Realising that doing something so simple could have such a positive effect astonished me back then. But it's something I've carried with me throughout my life, and enjoy the response I get (bar the odd blank look from the odd person - their loss!).

So how could you get the "it's nice to be nice" message across to the grandkids? Well, I've sold the idea to my own eleven-year-old daughter by writing these top tips for being an "Everyday Angel"…

Smile, please!
Even if you're nervous or shy, even if you're not sure what to say, just smile. It's the easiest way to seem friendly, and could really brighten someone's day. By the way, it works on dogs too; try it next time you see one on the street!

The power of hello, please and thank you.
As a child, adults will regularly ignore you, or even see you as a pest (don't be offended - it's not just you, it's every kid). But in your dealings with them, add a polite and clear "hello", "please" or "thank you". It will be noted. You will stop being invisible. And you might end up changing their opinions of all kids, not just you.

Say it, don’t think it!
You notice that a girl in your street has cool new shoes. Or a boy in class you don't usually talk to has done a really amazing drawing. Maybe your gran has a great new haircut. Well, don't just think it - say it! Compliments are like presents; they're SO appreciated. And they could make you new friends.

Be cross, but not for long.
Someone's been mean to you. It sucks and you're cross, naturally. But shake it off as quickly as you can, and get back to your normal, nice self. Everyone will see that the meanie didn't win. You did.

Imagine you're them.
You know your own feelings. But what about other people's? If someone's acting weird/stupid/shy/over-the-top, is there a reason? Before you react, take a second to figure out what might be going on with them. The biggest kindness you can bestow on a person is to see things from their point of view.

So those are my child-appropriate niceness tips. But re-reading them now, I'm wondering if I shouldn't wiggle them under the noses of a few adults I know!

We have three copies of Karen's new book Angels Next Door to give away to people who post on the thread.