Toning/Shaping muscles: Lots of Reps, Lighter weights.
Buidling raw strength and muscle mass: Few reps, heavy weights.
The second will NOT make you look good, it's what I used do.
I have 52" shoulders, and a 46" chest, but my stomach is also around 44-45". I have a 39-40" waist, and like 25" thighs. But I have a good layer of fat over my muscle.. I do not have a nice shape to my body.
But I could deadlift near 400 pounds, and bench over 250. This was my football workout. I was huge and very strong, but I didn't look good at all.
Now I'm not playing football anymore, so I wnat to shape up a bit. I do light weights, like around 100 on my legs, and 75 or so in the benches. Maybe 5-10 in the curls. I use very light weights but I do like 4 sets of 10-15. And that really helps tone muscle.
Also spend some time in the cardio machines. Rowing or Biking, it's good for the heart and it will burn fat.