Hello!
I'm 18, 5'7," and my weight is 190. I've tried diets and exercising, but I don't lose any of the extra fat. My upper arms are so fat that I wear long sleeves or sweaters to cover them.

How can I lose the extra fat and slim my arms at the same time?

First, I need to know if you are a male or female please?

There are several exercises to work on that area, is this the only area that is giving you an issue ?

Female

Well, arms belly and legs and face lol everything

Have you started with portion control on what you eat? Also try cutting out all drinks such as sodas and just try drinking water. Every time I am dieting like I am now, I cut to just water and I drop 10 pounds in about a week. It is a good way to kick start a diet. You could cut down on salt while doing this because salt helps retain water and a gallon of water weighs approxiamately 8lbs. So you don't want that extra weight hanging around. Try doing a little running at first and slowly work yourself up day by day.

I would discourage the working out of any kind at first, just until you have at least lost 10-15 pounds. The reason being if you work out, you will build muscle and it weighs more than fat so you would be gaining weight instead of losing it and that can be discouraging. At one point you will reach a brickwall and not lose any weight but don't let this discourage you, you have to keep moving through it and the pounds will keep shedding, you just need to stay with it. Also, don't worry so much about the pounds coming off as the inches. It makes you more confident in yourself and your routine.

I hope this helps you.