Your muscles, tendons and ligaments can tolerate more stress when they're warm. Start by lifting light weights. If you go too heavy, you'll have trouble walking to the breakfast table the next morning. So choose a weight that fatigues your muscles after 12 to 15 repetitions. Start with weight machines rather than free weights.
Machines require less coordination than dumbbells and barbells, so they're safer for beginners.
There's no chance you'll drop a weight on yourself or anyone else. Don't increase the distance or duration of your workouts, or the amount of weight you lift, by more than 10 percent each week. Mix up your workouts. But you need to embrace cross-training principles. Repeating the same activity day after day increases your risk for overuse injuries.