One thing that could make a difference is maybe splitting your routine into different days. For instance, you could have one day where you just work your biceps, triceps, shoulders and traps. Then the next day maybe work the legs by doing squats etc? That would give your body more time to repair itself than if you were doing the same routine every second day etc.

Also, I used to do 3-4 sets of 6-8 reps. You should be aiming to be almost failing on the last rep of every set, so maybe add more weight to get that result. I see your bicep curls are sets of 20? I used to just do 2 sets of 8 followed by a set of 6, and obviously used the weight that would mean I was almost failing on the last rep.