Borrow, adapt and test inducements for other kinds of businesses that you read and hear. Show your copy to people who will be honest with you, and ask if they understand what they'd be getting, on what terms. You may think the offer couldn't possibly be any more black and white, but if your way of stating the payment and delivery terms gets misinterpreted on the other end, you must clarify it further. Sometimes, as when you're offering information people absolutely can't find anywhere else, a tape, booklet or manual, or consultation can feel almost priceless to your market, even though it costs you next to nothing to make it available. Consider adding this kind of sweetener to your deal.
Guarantees make a tremendous difference.
Contrary to what you might expect, the longer the time stated in the guarantee, the fewer returns and refund requests you'll usually get. This doesn't mean you should put your business into peril, only that, providing you have a quality offering, you'll sell more with a reassuring guarantee. If you're in the position to sell something for an incredibly low price or astonishingly generous payment terms, explain why. Human beings procrastinate. But fewer do so when you toss in a special reason to pick up the phone or the pen right now.