No that it's it! It's just intervals of low intensity and high intensity it gets your heat rate as high as possible because of the sudden shifts in intensity and it's the fastest way to burn fat (and muscle if your catabolic).
I normally do about 15 minutes on a treadmill, at like 5-6 kph walk, 10-11 kph run.. start off first at 1.5 min walk, 1 min run and then slowly over a few months increase to 30 sec walk, 1 min run..
But it can be applied to anything, cycling, rowing, etc.
As for losing arm fat, or any part of your body, spot reduction is a big myth! The only way to lose fat is to lose it overall, working out certain parts of your body only increases resistance on muscles and muscle growth in those areas.
Generally you cut down as much as possible (eating 20% below maintenance cals and eat cleanly, avoiding sugars) till you are like 7-8% body fat and then eat normal maint. or above maint. cals to get back weight while working out and it should go to more feminine areas if your on HRT.
I was a real fitness junkie before when I was body building, I was lucky I decided to transition while I was on my cut so I was like 10% BF and lower end of BMI before I started HRT.
Also diet is a huge factor, eat as much whole food as possible (wholemeal bread, brown rice, wheat pasta) it is much easier on your metabolism and generally higher in dietary fibre and lower GI, also lots of lean meat and green vegetables. The easiest way to lose fat and you really don't even need to exercise and you will lose some fat is to CUT OUT SIMPLE SUGARS. Primarily, fructose, the sweet poison.. it gets metabolised entirely to fat and only small amounts get metabolised into glycogen.