1) There are two things that people can do immediately to build muscle
A) People can focus on both full body training and body part splits. We've knocked training "arms" for too long but the only thing that will make us grow is training a muscle with a big amount of volume. At that same time, we can also use an upper body day to get stronger. It is the best of both worlds B) People can sleep more. 10:30 is the magic time that you should go to bed by because it will allow you enough time to recover:30 and not getting up before 6 am will go a long way in helping us build muscle.
2) Train your legs more. Leg training is so essential for growing muscle everywhere. By training your legs hard you raise the anabolic signals in your body that tell you to grow. Heavy Squats and deadlifts are the beest way to build muscle. They raise your natural muscle building hormones, which cause you to grow
3) Use the correct sets and reps. We have to breakdown muscle to grow so we need to us high reps and a more volume based approach. So that being said I usually advise sets and reps like 4 sets of 8 reps or 6 sets of 4 reps. Remember, low reps can make us grow to simple because our body adapts to whatever we do for awhile so we need to change it up.
4) Use this secret trick. The first tip that I can give to everyone is that they need to be doing pull-ups or squats since these large muscle groups will help us grow everywhere. My best piece of advice is to tell everyone to do a back off set per exercise. Perform your last set of a exercise with higher reps of up to 25. Forcing more blood and sqeeuzing your muscle will force it to grow.
Building muscle is all about the quality of your workouts. Most people get caught up in the typical 3 sets of 10 reps dogma. While that will work for a certain period of time, it won't work forever. In my opinion, the best way to design your training for growth is to use 4-6 week spurts of volume phases where you train with sets of 3-4 and reps of 8-15. For the next 4-6 weeks, you should go with more sets of 4-6 and lower reps of 5-8. Both of these methods will lay you to have both muscle and strength gains.