Whatever it is that differentiates your advertiser from the competition MUST have consequences for someone!
Let's say your client's proposition is that their carpet showroom is BIG: there are many possible consequences for customers:
The manager would be hard to find so customers would have to yell his name to attract his attention.
There would be GPS satellites positioned above the showroom mapping it.
Customers would have to make way for the Google Maps van.
Each of those consequences is the seed of an interesting, memorable idea which will inevitably leave the listener with the picture in their minds that this IS a really Big carpet showroom!
And those are just some consequences for the customer.
Next consider what the consequences might be for the staff, for the family of the staff, for the customer's partner, podiatrist physiotherapist etc etc etc.