There are a few ways of doing this, one of the easiest is too carry out focussed exercises that will burn the fat on your arms. But the best way to do it, and benifit your whole body will be to follow a well structured weight loss program.
You need to look at your body as a whole, working on one selected area is not the way forward. If you have a lot of excess fat on your arms, I presume the rest of your body maybe overweight? Most people have parts of their body that they do not find attractive, and try to hide.
Not only will you get rid of your fat arms, but you will notice huge differences in other areas of your body by following a dieting program.
I can suggest a few exercises that will help tone your arms, if these are used in conjunction with whole body diet, you will be amazed in the changes in your body shape.
Engage in some light weight training exercises. Consult your gym instructor if you have a membership or invest in some weights for your home. These workouts should last for 30 to 45 minutes to ensure the highest amount of fat burning.
Carry out curls (for your biceps), and kickbacks (for your triceps), start with light weights first and slowly build up. This sort of exercise is great for toning, and banishing those flabby bits!
Remember it is mainly down to you. Motivation is the key to get rid of fat arms. As I said, find a weight loss program to suit you, along with exercise and your results will be outstanding.