Because of the heavyweight reputation, many lifters believe that they should train this smaller muscle group with the same volume and intensity as leg day. This is a huge blunder.
Even if you've done weight training before, you might not realize that your shoulder joints and muscles are not only smaller, but also much more delicate than other commonly-trained body parts, so we can't put the shoulders through the same rigors as other muscle groups.

Mistake #1: Poor Form When Performing Lateral Raises
Because the delts have three heads—anterior, lateral, and posterior—a variety of lateral raises are very effective for building both massive and proportionate shoulders. Lateral raises, on the other hand, are one of the most “abused” exercises in gyms, simply because trainees perform them incorrectly.
Guys frequently use excessive weight to achieve full range of motion, or they swing dumbbells up instead of using strict muscular power. Some guys will even turn their hands away from the floor rather than keeping them facing the ground, which fails to properly “isolate” the targeted head. In short, ensure that your form on all laterals is strict, complete, and precise.
Mistake #2: Disregarding Overhead Press
Focusing on compound exercises is one of the best methods any bodybuilder can use to build incredibly developed muscles all over. One of these exercises is the barbell military press.
You're limiting your shoulder development if you don't do barbell military presses. Is it a simple exercise in which you simply fling your arms? No. However, it is an exercise that will develop your shoulders beyond the majority of isolation exercises, and it is also a functional exercise.
Mistake #3: Not Using Appropriate Equipment
One of the reasons most top bodybuilders today have much more impressive shoulder development than in previous eras is the incredible variety of new equipment we are so fortunate to have at our disposal. While barbells and dumbbells remain the foundation of any intelligent mass-building program, the delts respond well to the various angles and planes of motion provided by machines and cables.
Too many people become accustomed to repeating the same basic exercises, even when they are no longer progressing. If you want to break through plateaus and continue to grow, make use of everything your gym has to offer in terms of shoulder training.
Mistake #4: Ignoring the Rear Deltoids
This is a very common mistake. Because the rear deltoids aren't a showy muscle, they're frequently overlooked. However, if you intend to compete in bodybuilding or simply want to look good from the back, training the rear deltoids is critical. This muscle can really set your physique apart from those who choose to ignore it.
Bent over dumbbell raises, upright rowing, and lateral raises on an incline bench are all good rear delt exercises to start with if you want to build a strong pair of rear delts.
Mistake #5: Not Warming Up
Although working the rotator cuff muscles will not directly improve the appearance of your shoulders, it is critical for your overall mobility and muscle health! If you don't warm up your shoulders with various internal/external rotation movements, you risk developing severe shoulder joint pain (or worse)—and nothing stifles your progress toward massive delts like serious joint pain. Spend some time working those rotators, and your shoulders will be pain-free and ready for battle.

Tips to Maximise Shoulder Training
- Work on your rear delts.
- Raise a barbell above your head.
- Use a full, yet safe, range of motion to perfect your form.
- Shoulders should not be trained immediately after the chest.
- Don’t train with weight that is too heavy for you.
- Keep shoulder volume low so they can recover properly.
- To remove momentum from lifts, sit down and slow down.
- Use strict form and avoid cheating, even if it's just to extend a set past failure.
- Perform a variety of shoulder exercises.