When you are wanting to get good muscle tone only, then you want to use low weights and do lots of reps, look at 5 sets of 20 reps.
The weight needs to be such that you find it hard to complete the last 2 or 3 reps of your last set.
For upper body tone all you need are one set of dumbbells.
With these you can train most muscles in your arms, shoulders and chest.
You will also find that press ups and sit ups are good ways to train the muscles you may find hard to train with the dumbbells.
If you are wanting to increase muscle size at the same time as gaining more tone, then you will need to think about the training you are doing, and train the right muscles.
You will want to train the top section of your triceps, you can do this either with sit ups or with your dumbbells.
To work your triceps with your dumbbells lay flat on your back holding the dumbbells by your side your knuckles pointing at your toes, keep your elbows on the floor as you lift the weight.
As you lift the weight twist your hands so that once you get your hand pointing up your palms are facing each other.
Then lift so that your arms are fully extended, while lifting you need to rotate your arms again so that your palms are now pointing at your toes.
Do exactly the same but in reverse to bring the weight back to your sides.
Do not use weights that are too heavy for you as dropping the weight when your arms are fully extended could mean you drop it on your own head.
You will also want to be training your biceps, you can do this with simple bicep curls.
I would recommend that you do 5 sets of 8 reps, although some people find 3 sets of 8 reps works best for them.
The correct weight for this particular exercise will mean that you can only achieve 6 reps on your last set.
You will need to do two lots of this exercise in each training session.