I build open wheel racers before 1970, and classic 1920s and 30s custom body cars in 1/24 or 1/25 scale. I've found the best finishes for car models depend on a dust free modeling environment. Make sure you have a clean, dust free space to paint in. Choose a good primer, and never try and get all the paint on in one heavy coat. This is especially true for gloss paints-- I give the model car body a light mist coat of about 50/50 thinned mix, let it dry thoroughly, and if there are errors, I use fine steel wool (0000 grade or finer) to polish them out, then I rinse the car body in warm water and let it air dry. I apply a second coat, and if necessary repeat the process. I never use fancy sanding or polishing compound techniques modelers sometimes resort to, nor do I use actual lacquer car paint. I find these finishes often come out "over done" so to speak for scale effect. On occasion, if I want a "metal flake" effect, I've used appropriate shades of acrylic nail polish thinned with Tamiya thinner (borrowed from my wife's large collection), but usually my choice of paint is Model Master enamels or Tamiya gloss. Finally, when I have the finish where I want it, I apply a final coat of clear gloss. My favorite clear gloss to date is Alclad gloss-- it goes on smoothly, self levels and leaves a crystal clear thin finish--unlike other gloss coatings, it can even be applied over clear parts . I've also used Future (Pledge with Future now in the States), which gives a similar gloss finish, but it takes longer to dry, requiring you to cover the model in the drying process less some wayward dust gets to the model. In fact though, it's a good idea to cover the model between paint applications anyway, that way no stray dust particles can affect the finish. I use a large inverted clear plastic bin to cover my models during the painting process. I recommend clear, because you can see what's underneath the bin, which will prevent you from inadvertently bumping or disturbing the model while it's sitting there (let's just say I've managed to bang up more than one model under an opaque bin in the past). Hope this helps a little.