When blasting your delts, try starting with standing side dumbbell raises. Alternate arms with very slow and deliberate movements.
For correct form, be sure to raise dumbbells to nose-level and keep your elbows straight. Use 2-3 working sets and for an extra pump hold the weight in the top position for 3 seconds or so on the final few reps of each set.
You can also vary standing side dumbbell raises by bringing the arms slightly forward at an angle. Shoot for a grove about halfway between side raises and front raises. Use light weight initially to really feel the movement.
Deltoids respond well to light and moderate poundage providing proper form is maintained.
On the standing raises, you’ll also benefit from experimenting with the hand and wrist position—try it thumbs down, palms down, palms up, etc.
This will change the angle of attack on your delts slightly and help add variation into your program. With this in mind, you should also try the various lateral raises while seated on a flat bench—this often helps you to maintain proper form and really isolate the delts.
Try this next time your at the gym warming up delts to get a sense and feeling of the different heads being worked.
Take a 10 lb. dumbbell in one arm and raise it in front of you up to shoulder level. While keeping the height of the dumbbell steady, move your arm first across your body towards your opposite shoulder . . . you should feel the very front of your delt flex slightly. Now keeping your elbow straight, move your arm outward towards your side . . . you’ll feel the tension in your shoulder shifting.
While you’re doing this, you can also rotate your palm and wrist from thumb-up to thumb-down and take note of the different deltoid heads tensing with the varied hand position.
Place your opposite hand on your flexed shoulder to feel how the delts respond to the various positions of the arm and hand.