how much weight you should increase by can depend on the particular exercise or the muscles involved. nonetheless the best course of action would be to increase the weight slowly and gradually. this may involve some trial and error but keep in mind that in some cases you can increase by 2. 5 - 5 pound increments. besides increasing weight consider adding more repetitions to your set at the current weight you’re at. try alternating between using machines and free weights for the same exercise as well or just try working the same muscle in a different fashion to promote further results. be sure to have someone supervise or “spot” you while you lift. unlike aerobic conditioning where duration and intensity is increased by 10% increases in the weight you lift aren't prescribed with such precision partly because muscle groups vary so much in size and strength and partly because of the practical matter of the weights available at the gym. typically you increase to whatever dumbbell is next on the rack (or plate on a weight machine) so if you're lifting 12 pounds with biceps curls then the next dumbbell available is usually 15 pounds. there is an option to increase in smaller increments with dumbbells by using an accessory called a donut a magnetic 1¼ pound weight that attaches to the end of the dumbbell (they come in other weights besides 1¼ pounds as well). weight machines have half weights for the same purpose. ask your gym manager to purchase donuts if they don't have them.
when i’m ready to increase the amount of weight i’m lifting how much more weight should i add?