Been training for 6 months or so, did a picture for progress and quite noticeably my upper back isn't getting larger on my right side more so than my left. Any tips ? 

It is not that the right is getting larger per se. Your right scapula hangs lower and more inward than your left causing the right Trap to look bigger than the left. I have the same bio-mechanical set-up. If you are not noticing more weakness in the left side when you do back training, then the two sides are developing evenly. If you are right-haned, the right side will tend to try to pick up more of the slack of a movement when both arms are involved.

The best way to counter and perceived/actual muscle imbalances is to train with dumbells and not barbells or machines which do not allow each side to move independently. DB rows of all various types as well as DB shrugs will make the left side move the weight on its own without any assistance from your right side.

John

@joee John has given you some good tips. Personally I don't see a major difference between the two, apart from the scapula positioning perhaps. Do you do much mobility work for your scapula/shoulder/rotator cuff?