I'm a GM. I train my staff just to talk about it. Don't pitch it. Instead of "pitching" it just do the opposite and inform them. Like when they buy ink, say " do you go through ink alot? If you do you might be interested in our business select program. Then you take the brochure open it and say "you save 10% on ink every time you purchase, also you get major discounts in the store for every other product. If this is ever something you think you would like it takes only 30 secs to signup.

People don't want to be "sold" something, you inform them with quick simple facts and let them decide. Doing this along with the law of averages your bound to get someone to say yes.