That's tough. I'm a runner and I work out, so I have only fat really on my butt (which is so naaaai [nice], lol). It's tough, because I don't have the fats hips, the round arms, and of that. So I just build muscle and no fat...
All I know is that you ought to try running, swimming, biking. Everyone looses fat the same way; cardio work out.
I drink protein shakes to help gain muscle. But that will turn into fat if you don't consistently work out AND drink the shakes. It takes a >-bleeped-<load of dedication and consistency (especially if you're not on T!).
Hmm... I do see this arm fat you speak of. I'm very thin, but I do have a small membrane of it. I'd say toning that area is the best any of us could do until we're on T. Mine doesn't flap around because it's toned. But my legs are pretty... ugh. Cisguys are so lucky, they get muscles just from eating and doing everyday work.