Paint problems

Hi im painting a nissan skyline R32 that is a replica from the one in initial D. I think its a fujimi model. before painting the car i sanded it with 400 grit paper. Know after 3-4 light coats i can still see the scraches the sand paper made. How can i get rid of them or will they just go a away as i keep on painting? I also need to sand the paint because it is kind of uneven what type of paper should i use?

400 grit is way to coarse, i think you might want to go back over with 600 then 800, then 1000 grit. go lightly but make sure to get all the scratches before you move to the next.
next time start with 1000 just to get the body dull looking, it should be smooth to the touch.

Start with at least 600 and up. I prefer 800 for major sanding and all the other stuff is made with 1200. I'm using 2000 for removing dust from paint.

You should try to cover the scratches with primer. If it isn't too late and you already began with color painting.