As you make matches, you'll eliminate tiles and new ones will arrive from the top of the screen. You know this. What you may not have realized, though, is that there's an order in which you should make matches when possible. Instead of eliminating easy sets near the top of the screen as they arrive, watch for sets you can eliminate closer to the bottom. This increases the likelihood that you'll stumble into an especially lucky chain reaction near the top of the field, as new pieces arrive.