Firstly you need to understand the Physiology of the Deltoids. They are a triple headed muscle group with front, lateral (side) and posterior (rear). Many do the shoulder press, myself incl in the past because usually you can do heavy
weights and guys like to show off. If you really want to develop strong muscular deltoids than I advise the following;
* Upright Rows - Do these either with either a barbell, Smith Machine or using a floor pulley. Upright rows are pretty fucking good at adding mass to the shoulders, better imo than shoulder presses because your pulling instead of pushing upwards against the resistance. When you lift dont go (The bar) higher than the nipple line otherwise you start hitting the Traps. Go with a nice pace, dont rush it but use more explosive power at the start and take more of your time at the top when going back down to really feel it in the muscles.
I dont know what principles you work by i.e. HIT, HVT, break sets, pyramids or whatever they use nowadays. I'm a HIT man myself but everyone is different and respect to ones methods but aim for failure when training the shoulders, until you feel that burn and cant lift any more and than try to squeeze another rep out and hold it before going down.
Upright rows target the front deltoid the most.
* Lateral raises - Perform these sat down on a bench so that your chest is leaning into the back support. This makes it more strict. Your sat up straight but with your
weight into the support. Now raise the dumbbells out with your left hand to a 10 O'Clock direction from you and the right to a 2 O'Clock direction. Elbows slightly bent inwards to allow this but arms are straight so not drooping down.
Importantly tilt the dumbbells forwards because this than places the
weight on the lateral head. So raise the
weight out to your side and tilt the wrist forwards. This method was devised by the great late Vince Gironda and I have built really wide shoulders from it.
You also dont need really heavy
weights for these, you wont lift them but aim for failure again.
Arnold Presses - Work the entire 3 heads of the shoulders and better than the standard dumbbell press. Just search the net for an explanation of them.
Lastly you can do a specified rear delts exercise but you dont need to really because with the other stuff they do get worked, especially if you work the back already and do chin-ups but for the rear deltoid is simply bent over lateral raises. Usually done standing right ... well use a bench. Lie down on the bench and perform it as though your leaning over. This makes it stricter with no cheating.
Upright Rows (Front mostly but works all)
Seated Lateral Raises (side)
Arnold Presses (All)
-
Lay down Lateral Raises (rear)
If you want to work the Traps and you should because it will close the gap between your shoulders and the neck otherwise huge shoulders with small traps looks stupid. Do either barbell or smith machine shrugs with heavy
weight or better still what worked great for me was Hise Shrugs on either a power rack or smith machine. The barbell is over your shoulders like a squat and you shrug your shoulders up, essentially taking the weak link (Hands) out of the equation plus you dont half feel it.
Let us know how you go.