I paint in my garage. To eliminate dust I have a metal spray booth But I dont use the fan. It's just a box for me. But first and foremost take a windex bottle, fill with water or 50/50 mix or what have you. Completely spray your work area. Spray the air, the ground, and inside your box. Anywhere you could see yourself kicking up dust. Even your sleeves. The point is to trap any dust that could fall on the car body. Secondly if you have an air compressor. Wash your car body before painting and set your airbrush to a high psi to blow the water off. Make sure the water is all gone. Then paint immediately. When you finish painting let it cure enough to at least get some initial orange peel. If you move the body right after spraying you aren't helping yourseIf. Ive done this for about 2 years now and I've eliminated most dust issues. I still get a hair occasionally but this works 95% of the time.
Great start I made a how to thread on AF a few years ago describing how to correctly paint the headlight buckets on this kit if you want the modern look. Give it a whirl. http://www.automotiveforums.com/vbulletin/showthread.php?t=1110998&highlight=Painting+tamiya+supra+headlight
The biggest thing I can recommend to a beginner to make the leap into higher quality model building is too simply hold yourself to higher standard of building. Do not allow yourself to accept mistakes and flaws. If you mess up, strip it down and paint it again until you get it right. And with that I do believe comes buying quality paints and airbrushes. If you are trying to get serious about the hobby you need a workhorse gravity feed air brush. I know a lot of people will say you don't but if you want to get really good you need to give yourself the ability to do that. I would agree with the OP that studying your subject is a must. One thing that I do. The one standard/minimum goal that I have to accomplish with a model is that it must look like the real deal from the outside. That means a quality paint finish, removing and or filling panel lines that do or do not exist on the real car. Quality products are a must. That doesn't mean you have to get real expensive you just need to know what to buy. For beginners reading this thread. For interiors and engines, stick to acrylics. Vallejo has the best acrylic brush paints you can buy. Their model air line has premium opaque colors perfect for interiors too. Tamiya acrylics also allow for a variety of metal finishes. Tamiya TS line and Duplicolor are awesome for body colors. I like the testors lacquer line too but most of their metallics are out of scale. Personally I still use spray cans for bodys(mostly) and use my airbrushes for interiors and engines. And there is no substitute for Tamiya masking tape. Lastly you have to treat the model as a work of art, every piece of it. We are artists, we just paint on models. The whole hobby is a lot like golf in my opinion. You need a lot of patience, practice, and decent clubs(supplies). You are competing against yourself and no one else. Take as much time as you need to make the model the way you want it to. Rushing will only lead to disapointment.
With the white and yellow paints you need to undercoat them with a more opaque color first. Or you simply need to slowly build the paint up with watered down coats first. I stand by Vallejo paints. They are the best brushing paints in the business.
What color is the paint? Did you apply a clear coat on the first paint job? I would mask off the panel that needs to be retouched. But be careful how many layers of paint you add to touch it up. You'll need to do light coats to build a base and gradually return the spot to the same depth of color as the rest of the paint. If you put on too many coats you may have a piece of the car that looks uneven. And in that case you would need to respray a whole section of the body to blend the whole thing back together. If you sanded through clear coat on a metallic paint job just make sure you do light coats because spraying metallic paint over a clear coat on itself will tend to give it much more depth which can appear uneven. The section that you respray may end up looking like fresher paint than the rest of the car.
In my opinion OP it was the paint that caused your bleed through not the clear. I've had this issue with Duplicolor paints many times. It might have something to do with how heavy your coats are but you will get ghost lines and "bleed throughs" if you are not careful. I would use primer sealer on any body you want to paint with a duplicolor lacquer.
1500 is sufficient but I take it 3000 now because 3M has come out with a 3000grit sponge pad that makes sanding a whole lot easier. Testors metalizer is the very best paint to use if you are wanting to paint a car body silver. It's the only thing I've seen that truly matches an "in scale" grain for a 1.24 car body.
Here's a tamiya NSX i painted with aluminum metalizer non buffing. Primed with Zero primer and wetsanded with 3000 grit. Cleared with testors wetlook.
Metalizers are designed to be sprayed on bare plastic.
If you are priming the surface first you need to sand it down up to 2000-3000 grit or higher. The metalizer is an extremely fine grained silver. It will show any imperfection or paint (primer in this case) texture underneath it.
Honestly I just judge it by feel. If you've put on a couple of heavy color coats just let it gas out for a few days then apply clear. Waiting for weeks isn't necessary and I haven't had a problem with it.
The problem with ts-13 is that it is "hot". it can and will destroy decals. This is why wetlook clear maybe more suitable in that application.