Before you ever hitch your horse to a cart, you have a lot of training and ground work to do. Driving is inherently more dangerous than riding, so it's extremely important to get it right. If you fall off your horse while riding and he gets loose, it's a problem. If you fall out of the cart and the horse takes off attached to a large rolling object, that's a much bigger problem.
Assuming your horse is already broken to halter and knows basic commands, start out training him to drive with long lining. Your horse has his bridle on and a surcingle on his back, through which you thread the long lines. Carry a driving whip as an additional aid -- not to hit the horse, but to gently guide him in the direction you want him to go. Stand behind your horse to one side, far enough away so he can't kick you. Start your ground work in a round pen or ring. As you progress from simple starting and stopping and turning in different directions, you can add figure eights, poles and serpentines to the mix. After your horse is comfortable in the ring, further conduct this ground driving practice around your farm and neighborhood. Your horse must be comfortable and calm with ground driving before you can proceed with hitching him to a cart.
Although you don't have to purchase the most expensive harness available when training your horse, make sure it is safe and sturdy. High-quality leather harnesses are a good investment, but avoid cheap leather because it breaks easily. Harnesses made of leatherlike synthetics are affordable options. Your horse will learn the feel of the crupper under his trail and various straps along his body, as well as blinders on the bridle. Blinders keep him from seeing the cart directly behind him so he focuses on what's ahead and is less distracted. After he's used to the harness, start ground driving him with it.
Actually pulling the cart is the scariest aspect of driving for green horses, because they are attached to this large, noisy thing behind them. Let your horse become familiar with the cart long before you ever attempt hitching. Let him look at and sniff it so he becomes used to its presence -- you can even feed him out of the back of it so he thinks of the cart in a positive way. Before your first attempt at hitching, ground drive your horse while an assistant picks up the shafts and follows you with the cart. That way, the cart is behind your horse, much as if he were attached to it, but if he freaks out because of this rolling monster behind him, your friend can simply gently let down the shafts. If he's fine with the cart behind him, you can try hitching him after another practice session or two with an unattached cart. If he can't deal with the cart behind him, he probably won't make a driving horse.
Always harness and hitch your horse in the same way, developing a routine. That helps prevent your accidentally failing to leave something undone. Check your harness carefully when putting it on, looking for weak areas that could break. Use a similar routine when taking the harness off. In addition, check your cart, especially the wheels, for any signs of loosening or wear.
Although it's tempting to train a horse to drive yourself via the use of books, videos and the Internet, if you and the horse are both novices, find a professional to help you. There's an old equestrian saying in these circumstances: "Green plus green equals black-and-blue." Contact a driving club in your area for advice, or attend driving clinics and inquire about good local trainers.
Jane Meggitt has been a writer for more than 20 years. In addition to reporting for a major newspaper chain, she has been published in "Horse News," "Suburban Classic," "Hoof Beats," "Equine Journal" and other publications. She has a Bachelor of Arts in English from New York University and an Associate of Arts from the American Academy of Dramatics Arts, New York City.