If you are operating an ATV, it is extremely important to get the proper training. Training is available with the purchase of a new ATV. If you acquire a used ATV, training information is available at ATV Safety.gov (http://www.atvsafety.gov/index.html) and the Specialty Vehicle Institute of America (http://www.svia.org/).
All the Gear, All the Time (ATGATT) cannot be stressed enough! Wear appropriate riding gear, including an approved helmet, goggles, gloves, over-the-ankle boots, long-sleeve shirt, and long pants. According to AR 385-10, during off-road operations, operators and riders must use additional PPE, such as knee and shin guards and padded full-fingered gloves.
In addition to getting training and wearing the right gear, you need to check your local laws. Some states may require Off-Road Vehicle decals and have designated riding areas. Many ATV accidents occur at places other than approved riding areas.