Muscle growth is a mix of art and science. No two people are the same. BUT there are 4 fundamentals that provide the foundation for muscle growth.
Consistency is a key component to muscle growth. We need routine. But when muscle growth is the name of the game, you have to consistently challenge yourself. Our bodies adapt quickly to the amount of weight we lift, the muscle group splits we do, etc. Try altering variables of your workout approximately every 4-6 weeks. This will keep your body guessing (and progressing). Add in new exercises, or switch the order and approach to your gym sessions. Even if the foundation of your workout remains the same, simply adding techniques like drop sets, pyramids, etc., helps spice up your workouts so you can avoid plateaus.
You can train all you want but if you don’t have the proper nutrition, you won’t achieve the best results. A well-rounded approach to nutrition, one that includes an assortment of lean proteins, whole grains/complex carbs, veggies, fruits, and heart-healthy fats is essential. It is also important to structure your diet around your workouts. You need to reload with carbs and protein within an hour of your weight training session. Replenishing those glycogen stores post-workout will help with muscle recovery and muscle growth.
Supplement the right way. In other words, know what you are taking, why you are taking it, and how to time your supplements appropriately for your goals. Don't just take something because your friend is taking it. A one-size-fits-all approach to supplements won't get you the results you want. Do your research and find the supplements that best match your personal fitness needs!
Make sure you are getting enough rest and are recovering properly post-workout. Aside from getting a decent amount of sleep each night, taking a rest day away from the gym has its benefits too. Don’t forget it is during rest that our muscles are able to rebuild.