The first thing you need to understand thermo boy, lol, is that everybody is a little different. Unfortunately, there is no magic formula and if there is please let me know because I haven't found it and I've been doing this for 17 years, boy am I tired lol
I think you need to lower the reps and try working in the 6 to 8 range, like Prince said. I think you should go with 3 exercises per muscle group and stick with dumbbells and cables. Barbells are great because you can do more weight with them. But with dumbbells you get a better range of motion so they work the muscle(s) harder. Also with dumbbells you can not cheat the weight up like you could with some barbell movements. Cables are great because you put constant tension on the muscle(s) throughout the positive (concentric) and negative (eccentric) phases of the lift! Increase the weights on the exercises to work the muscles harder and use a weight so when you approach that 6-8 rep range, you go to muscle failure. This will overload the muscle and force it to grow!
Try this routine out for a while. Let me know, either by AIM or posting on the board, how it's working. If it doesn't seem to work for you don't worry because I have many ways to torture a person, LOL
CHEST
1. Incline dumbbell bench press 4 sets, 6-8 reps
2. Flat dumbbell press 4 sets, 6-8 reps
3. Incline dumbbell flies 4 sets, 6-8 reps
Every third chest workout, for 1 workout only, do the following and then go back to your regular chest workout:
1. Incline dumbbell bench press
2. Flat barbell bench press
3. Cable crossovers
Same number of sets and reps
This alternating schedule will shock the muscles because they will be use to doing the regular schedule!
SHOULDERS
1. Seated dumbbell shoulder press 4 sets, 6-8 reps
2. Upright rows, (try the smith machine or a straight bar) 4 sets, 6-8 reps
3. Seated dumbbell lateral raises 4 set, 6-8 reps
Every third shoulder workout do the following for 1 time and then go back to regular schedule:
1. Military press
2. Front cable raises
3. barbell shrugs
Same number of sets and reps
Try this for a little while and let me know how it works out, good luck
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If you build it they will come