Chipping, especially from longer distances, requires a lot of feel. You need some wrist action to control the distance, spin and trajectory of the shot. Unfortunately, many golfers overuse their wrists. The left wrist breaks down at impact, causing them to blade or chunk the shot.
Your goal should be to keep your left wrist relatively firm through the swing, which helps you hit down crisply on the ball and keep the clubface square to the target. It's much easier to keep the left wrist solid by chipping with a putting-style grip, which is a variation of the common Vardon (or overlapping) grip. Simply invert the pinky and index fingers that connect your hands so your left index finger rests outside your right-hand fingers (called the reverse-overlap grip). You'll keep your left wrist firm.
Everything else is standard for chipping -- slightly open stance, ball position well back of center, a little hinging of the wrists in the backswing, etc. But the grip change will stabilize that left wrist for more predictable contact.
David Leadbetter is a Golf Digest Teaching Professional based at ChampionsGate near Orlando. He operates 26 golf academies worldwide.