Ever tried pyramids?
start with light weight and high rep count (e.g. 21 reps)
rest for 30 sec.
use moderate weight with moderate reps (e.g. 13 reps)
rest for 30 sec.
use moderate to heavy weight with lower reps (e.g. 8 reps)
rest for 45 sec.
use heavy weights with low reps (e.g. 5 reps)
rest for 45 sec.
use moderate to heavy weight with lower reps
rest for 45 sec.
use moderate weight with moderate reps
rest for 30 sec.
and finally, use light weight with high rep count
try this and if you really wanna burn your traps then you could try doing a second set of the pyramid, only this time you start with heavy weights, lower it till you get to lightweight and then go up again (5 reps, 8 reps, 13 reps, 21 reps, 13 reps, 8 reps and finally 5 reps) resting exactly the same amount of time for each specific weight (heavy = 45 sec, light = 30 sec).
Hope this helps. Shrugs and barbell/dumbbell upright rows are classics that never fail as well but sometimes you need to do supersets or something like these pyramids.