You have to realize we are not all born with the same amount of recuperative ability. Just as there are giants on one end of the height spectrum and midgets on the other end of the spectrum, there exists a spectrum of recovery ability. If you want, you can use a split similar to what you have, although I would suggest you try working thighs, back and biceps on Monday and Thursdays then on Tuesdays and Fridays work on chest, shoulders, triceps and calves. Work abdominals roughly 3 times a week.
If this doesn't result in gains, you are clearly not a "recuperative giant" so cut the frequency in half so you have the same split routine but only Mondays for thighs, back and biceps and Thursdays work chest, shoulders, triceps and calves.
I this still doesn't work you may be a "recuperative midget", also known as a "hard gainer." In this case I suggest experimenting with giving each muscle group up to 8 days rest, with maximum of a total of two workouts (each working roughly half the body) each 8 days. This will allow 96 hours between workouts, and 192 hours between working the same muscle groups.
There is no need to do more than two sets per muscle group, excluding warm-up sets. The is not an endurance contest. The objective is to achieve the stimulation of muscular growth. Once you have stimulated muscular growth, love the gym. Doing more steps (just because you feel you can) will only serve to cut into your limited stores of recuperative ability.
AS for how many reps to do, many books will tell you to do 10 reps. 10 reps is an even, easy to remember number, but it is also totally arbitrary. In each set, after thoroughly warming up, work each set until you are unable to accomplish one more rep. Only this level of intensity will ensure you have reached the necessary level of intensity required to stimulate muscular growth. Remember, growth must literally be forced. If you could curl 60 pounds for 8 reps and never tried for a ninth rep, continuing to curl it for 8 reps in each biceps workout, do you think your biceps would grow and get stronger? No! They would have no need to do so. It is only by placing a greater stress on them than they are currently able to do by giving your all to attempt that 9th rep that the body is forced to adapt by growing larger and stronger.