rough body

i've painted the body of the tamiya honda s2000, but is all rough; What I have to do for do it smooth and shiny?

Assuming you sprayed since you don't say, and plus, if you brushed it then you should expect it to be rough :)
It sounds like you may have been holding the can/airbrush too far from the model and so the paint is drying slightly before landing on the model, and so it is not smoothing out on the surface.
I would recommend a light wet sanding to even it out, then to rinse and dry the model to remove all the sanding dust. Make sure it is completely dry, then I would recommend that you try giving the model another coat while spraying a bit closer to it, but not too close....
Just remember that if you get too many coats of paint on, you will start to lose the detail, be careful of this and only strip the paint if you have to.
Hope this helps:)

Ray

Hey!Look that The body isn't very rough; it has only a little orange peel

Hey!Look that I was only answering the question as you asked it, you should be more specific if you want a more specific answer.......
wetsand the area with the orange peel to even it out and then rinse and dry the whole body to remove any dust. thoroughly dry and paint a final coat......DON'T hold the can/airbrush too far away and make sure you get an even coat or you will just get more orange peel.
Question answered? I hope so......just trying to help.

Sorry to be off-topic, but...

Where are you from Luka3000gt? What is your native language? Do you know english, or are you using a translator? :)

I'm Italian and I know english; but I don't know the specific words

Hey, at least that explains the Lancia for your car:D
Don't worry about it, I don't think there is anything wrong with your English, I am English and speak 2 other languages, I get them screwed up a lot more than you do English.
I hope my answers above helped you?

Ray