Always do your exercises through a full range of motion in a slow, controlled manner. It is far better to start out too light than too heavy. Choose a weight that you are sure is light and do a warm-up set of 15 repetitions, while perfecting the correct lifting technique. Going to total muscle fatigue with a challenging weight is not a useful objective in your first few weeks. When trying a new lift or starting a new routine, the objective is to practice and perfect your technique, and to learn how to concentrate on the muscle you are exercising.
Proper breathing is essential in weightlifting.
If you hold your breath while lifting a weight, you run the risk of raising your blood pressure and starving your brain of oxygen. Do not leave equipment lying around the weight room where someone could trip over it. Always use the collars that prevent weights from falling off the barbells. Be sure to keep your hands away from the chains, cams, pulleys, and weight plates of exercise machines when they are in use. Also, when selecting the weight for a machine exercise, be sure to push the pin in all the way.