Just do it. Snap! Crackle! Pop! Think different.

The all-time best advertising slogans are unforgettable. They’re some of the most ingenious, perceptive and persuasive words ever written.

Some even achieve slogan nirvana and become everyday expressions. ‘The customer’s always right’ was a Selfridges advertising slogan that spurted out of a sloganeer’s pen way back in 1910.

Slogans are micro-narratives – very short stories. They’re tricky to get right. And the trickiest thing of all? Making sure your story doesn’t go in one ear and out the other. You’ve got to make sure it’s sticky because unless people remember what you tell them, they won’t buy your product or support your cause.

In the charity world slogans are called straplines. And more often than not they’re humdrum, characterless and self-evident. Carers UK’s ‘the voice of carers’, Shelter’s ‘the housing and homelessness charity’ and Kidney Research UK’s ‘funding research to save lives’ aren’t sticky at all.

I reckon we’d  get to those sticky stories if charities stopped thinking ‘strapline’ and started thinking ‘slogan’.

Strapline is an extraordinarily boring word, so it’s no surprise that a lot of charity straplines are, in the same way, boring, functional and undemanding. Slogan has more oomph. It’s a rallying cry. And it calls for bravery and imagination. A sticky slogan has the potential to create real enthusiasm for a cause. Maybe it can even change people’s behaviour.

A few years ago I advised Social Enterprise Coalition to change their name to Society Profits. In the end they decided on Social Enterprise UK but reinvented ‘society profits’ as their slogan. It tells you everything you need to know in just two words.

A charity’s name and slogan need to work together. Its slogan can even be a continuation or an extension of its name. I renamed National Schizophrenia Fellowship as Rethink and added the words ‘severe mental illness’. Their full name, Rethink severe mental illness, is also their slogan – their rallying cry. The result has been a huge boost in awareness and support.

I’ve got a formula for inventing sticky slogans: idiosyncratic + ruthless = unforgettable. Your slogan has to be idiosyncratic; that’s to say, it must be so individual and characteristically ‘you’ that it just can’t be mistaken for anyone else’s. And you’ve got to be ruthless in uncovering your story and finding the words to make it unforgettable.

John Spencer is the founder of Off the Top of My Head. He invents names, creates logos and graphic identities, and conjures up campaigns.