End your sales copy with a discounted price. Just list your regular price in the middle of the sales page and then offer a discounted price off the order if they order ‘right now’. You could also offer a rebate that takes effect instantly.
For example, you could say, "Instead of paying $99, you could order now and get an instant rebate of $20 - you only pay $79!"
Use a "P.S." at the end of your ad copy. This is where you either want to repeat a strong benefit or use a strong close, like a free bonus. For example, "P.S. You can get (product), worth over ($), for the low price of ($)!" Another example, "P.S. I can not guarantee the (No.) bonuses will be here tomorrow!"