First, make sure you're signed up for Amazon Prime. If you're not already a Prime member, you can sign up for a free 30-day trial. Once you're a member, you'll be able to start shopping on Prime Day. To maximize your rewards, look for deals that offer bonus points or miles. For example, some cards offer 5x points on Amazon purchases, so if you find a deal that pays out 10x points, you'll earn 5x the usual points.