After suffering a shoulder injury and re-evaluating some exercise science stuff I have read I have tried a particular shoulder exercise for delts for the last few months and I have concluded that they have been the most effective for me.

I had to stop pressing all together and balance my shoulders out so my front delts dont grow any more and only trained side and rear delts and my side delts have never grown so fast, the way I am training them is actually by isolating them from the supraspinatus and traps.What you need is access to a cable cross over and do this exercise:

The trick being is to NOT do the 1st quarter of the movement and concerntrate on the 3rd quarter the most, the last quarter may cause impingement if you are prone but should generally be okay but is not neccesary.

Rep range should be on the higher side, you can also go a bit of an angle to include the rear delts but it is not too important.
If you want, do a static hold at around the 3rd quarter you might feel a good pump in your side delts.You can finish off with a lighter weight and do 1 set partials with only the 1st quarter of the movement every 2nd workout or so, so that you dont neglect your rotator cuff too much.

The idea behind it is that the rotator cuff shouldnt be able to grow to the same degree as the delt because it does not get as much blood flow so it can possibly hold your delt growth back.

Other exercises are capable of excluding the rotator cuff but they tend to include other muscle groups such as traps and forearms.Cables are fine to use and this I have found absolutely isolates the side delt the best without you needed to practically do a static hold on your forearms while keeping your shoulders safe.