Email campaigns can be really fun.
To keep your customers buying more, you should always recommend something else that would also be of use to them.
But don’t overload (see my post: on the paradox of choice).
What is an upsell?
Well if you’re selling a small version of a product your customers may very well be interested in a large. If they’re buying “LIGHT” why not offer them “DELUXE” instead?
Just don’t abuse this process. If you upsell crap (products of services that don’t offer a higher ROI for the money they are laying out) then they are gone forever. All efforts to regain your credibility will be in vain.
It says: here’s what others are getting. Are you interested?
What is a cross sell?
If you’re selling horses, wouldn’t your customers be interested in saddles? If you’re a dentist and you perform teeth, wouldn’t the same customer possibly be interested in teeth whitening?.
What are continuity products?
These are my favorite: Products that require subscriptions. In essence they are built-in guaranteed repeat sales. The reason they are so great is that you only have to pitch once, and the subscriptions come in monthly.
Magazines, Gym memberships, service providers are great examples.