need help with workout

i've heard and read so many ways i should workout.for the last 2 years ive been doing the following,monday chest,tuesday shoulders,wed.biceps and legs,thurs.triceps,and friday back and neck.so can i get some tips on how to better my workout,such as should i be resting inbetween these days and how many sets should i do,and how many exercises per muscle group.right now i do 3 sets of a weight 8 reps for a week then ten reps the next week then twelve and then move up in weight.this does work for me but its so gradual.help please!

just make sure your changing your exercises out every 12 weeks, i like to alternate exercises to start first, for example one day for chest start with flat bench first,then next week start with incline. change up your sets, rest intervals, and intensity to keep your muscles guessing. should search on supersets and periodization. the key is to keep your muscles guessing and growing.