Killer trap workout for me is:
Dumbbell in each hand, each Dumbbell weighing about 35% of my own bodyweight, shrugging the shoulders 1 x 40-45
Say you weigh 200lb, 200 x 0.35 = 70lb dumbbell in each hand.
Then doing military press, (lowering Olympia bar with weights behind neck and raising) 1 set of each:
60% of bodyweight: 8 reps
55% of bodyweight: 12 reps
48% of bodyweight: 10-12 reps
Just the bar itself: 16 reps
What you can do compared to your bodyweight will vary with your strength and muscle, please only note my advice as suggestions.
If you can't even do 60% of your bodyweight once then go way down and build it up gradually as your strength increases.