Concentration Curl

Sit on a bench so that your legs form a 90° angle. Place the right upper arm on your right thigh and pick up the dumbbell from the ground. Then curl up the lower arm without moving the upper one and squeeze your biceps when it reaches up, then lower it back to the starting point. Do this for a few reps and then switch to the other arm.
Cable Curl

You can do this in many different ways. If you are doing a standing curl, you can also use a pulley machine with a cable attached to it. Stand some feet away from it and grasp the cable in your palm. For better balance, you can put one foot in front of the other. Curl the arm and bring your hands closer to the shoulder. Stay in that position for some time. After doing this 15 times, change your hand and do the same thing.
Diet

Diet is also essential when you want your arms to grow bigger. When you want the muscles to grow, your body needs certain nutrients for it, so you should know what to eat at that time.
- Protein
Eat food that has protein in it to improve muscle growth. If you have any accidents during the workouts, it will speed up its recovery too. You can include fish, egg, beef, yogurt, beans, or chickpeas. The recommended amount of intake is 1.4 grams per body weight.
- Carbohydrates
Just like protein, carbohydrates are also vital for your body, especially when you workout. They provide energy to the body and strengthen the muscles. You can eat pasta, quinoa, green peas, oatmeal, or brown rice. Do not eat simple carbohydrates as they make you gain weight. Avoid candies, cookies, and sweet food. Complex calories have more nutritional value.
- Fats
When you workout, your body starts burning the fat down, but if you do not have enough fat, it starts cutting down protein. There are some healthy fats like salmon, peanut butter, and avocado.
- Calories
Your body needs extra calories to fuel the new muscle growth while also maintaining it.
- Supplements
Usually, when people want the process to be fast, they take supplements. If you cannot intake protein accordingly, you can purchase protein-based supplements and bars that are almost the same.
Conclusion
Some people are interested in having thin, strong arms, and some want their arms to be massive. You can grow your arms either way by staying consistent in your workouts. You need to exercise daily and also focus on your diet. This may not seem easy at first, and when you start doing the exercises, your body may ache for some time, but it gets better after a few days. Choose your exercises and start with doing it for 7-8 times in the start, and increase it gradually.
If you do not give up and keep working hard for it, it will surely come in good time.