Here are some of my favorite arm exercises.

If you want to improve the way your arms look, dumbbell curls are a great arm exercise. If your main goal is strength and lean mass development, aim for 4-12 repetitions.
If your goal is toning and endurance aim for 8-15 repetitions.
Starting Position:Simply begin by holding dumbbells in both hands.
Form: Exhale and slowly bend your elbows towards your chest. Hold briefly at the top of the motion, before slowly lowering to the starting position.
Tips: Move in a slow and controlled manner, keeping your elbows locked in position. If you move too quickly, momentum will take over and your biceps will actually work a less when momentum takes over.
One of the main compensations during this bicep exercise is arching the back to assist in lifting the weight. If your back moves, that is a sign that the weight is too heavy, so try a lighter weight or do less repetitions on the next set.
Bicep Curls with the barbell are a simple but effective biceps exercise.
Starting Position: Begin with your hands at shoulder width. Use an underhand grip.
Form: Exhale and slowly bend your elbows towards your chest. Hold briefly at the top of the motion and then slowly lower to the starting position.
Tips: Just like other biceps exercises, you should move in a controlled manner so that momentum doesn't take over.
In addition, you should be mindful of your posture and keep your spine stable by engaging your core muscles. If you feel your lower back moving, that's generally a sign that the weight is too heavy.
Some people prefer close grip bicep curls with the barbell instead of shoulder width.
At the gym, almost everyone loves using the cables in their tricep workouts. Cable exercises are great for toning flabby arms or building triceps.
The cables provide a constant tension that really challenges the triceps through the entire range of motion. And the cables really help you get a good burn or pump in the back of the arms.
Starting Position: Attach a rope attachment to the upper part of a cable machine. Hold the rope with your hands facing each other.
Form: Exhale and pull the rope down towards your waist. Hold for a brief moment and then slowly return to the starting position.
Tips: Keep your shoulders in good alignment during this exercise. The tendency is for the shoulders to tip forwards as you push down.
Also keep your shoulders stationary during this exercise. Only move your elbows to isolate and focus on the triceps.
Stand up straight and keep your back in good alignment, and always move in a slow and controlled manner.