Before you can use your irons effectively, you need to understand what they are. In golf there are two types of clubs: woods and irons. The heads on woods used to be made of wood and the heads on irons used to be made of iron; both types of clubs can be made of metal these days, and steel has replaced iron as the most common material. Now that you know what irons are, read on for tips on how to use them on the course.
For loft: Loft angle, in golf, is the angle of the club face as it relates to the vertical plane presented by the shaft of the club. Irons are designed so as loft increases the length of the shaft decreases. In general, the more loft a club has (that is, the greater the angle), the higher the ball will go in the air. The trade-off is distance; lower loft gives greater distance.
For control: The length of a golf club is instrumental in determining how far you can hit the ball. While the laws of physics dictate that a longer club will give you a longer range, in practice, that's true only if you can control your swing. A club that's too long or too short will cause your stance, and your swing, to be off-kilter. Irons are designed with shorter shafts than woods; having a few in your arsenal increases your options for hitting over various hazards common on a course.
For game improvement: Irons are designed in one of two ways, either with a cavity back or a muscleback. All irons have the same basic head shape, but muscleback heads have a solid back while cavity-back heads have, as the name implies, a hollowed out space behind the face. Accomplished players should choose a muscleback club. The solid head means there's more weight directly behind the point of impact with the ball -- a good thing if your swing is controlled, a bad thing if it's a little off-center. For less confident players, a cavity-back club is a better choice. In a cavity-back club, the mass of the club head is moved from the center to the edges (this is known as perimeter weighting). The heavier edges and hollow back mean the club head will twist less in response to an off-center hit, helping to keep your ball on course.