ok i go to the gym everyday... and obviously im doing split workout.... so today i noticed that for me increasing the intensity for my upper body is very difficult

i usually do 3 sets of 12 reps
today i tried:
peg fly
dumb bell curl
latpull down
tricep kick back

i am having difficulties on all of em except for tricepkick back

so what shud i do? i really wanna increase the intensity as it makes me feel better everytime i increased the weight

less reps more sets??