If you rush you could end up messing your stencil all up. The stencil is to aid you in creating your airbrush art and is a big part of the art process. If you have to then practice on a scrap piece of material till you get use to how the knife works and how to properly cut out the areas. This will help to ensure that you create a working stencil for your airbrush art. There are actually two reasons for the base coat. This base coat will help protect the nail from the paint and help the paint to adhere to the nail better. Metal should be wet sanded to give a rough grainy effect. This rough grainy effect will help the paint to adhere to the metal. With metal actually being smooth the paint will have a hard time sticking to the smooth surface. PSI stands for pounds per square inch and for automotive airbrush art you need a compressor that has a psi of 55-65. Iwata is a great name brand to go with and they offer four compressors that will work for airbrushing automotives. Badger is another good name brand that you can go with. They offer several air compressors that will work when doing airbrush art on automobiles. There are couple of ways that an artist can learn how to do micro airbrush art. One way that an artist can learn how to do micro airbrush art is to obtain a video created just to teach micro airbrushing. AirBrush Action has a video titled Micro Airbrushing that features airbrush artist Robert Benedict. Expert instructors include Peter West and Pamela Shanteau who hold classes at the Learning and Product Expo: Art for beginners through to advanced. AirBrush Action offers their Airbrush Getaway Workshops that run from a one day class to four day classes and are located in Las Vegas, Nevada. The workshops offered cover airbrush t-shirt art, murals on steel introduction, achieving photorealism, pinup art, pin striping and much more on airbrush art. While this is a very primitive method compared to modern day forms of airbrushing, it does still work. Take a look at children's airbrush art kits that require the child to blow through one end of tube to create the airbrushed art. Now ancient forms of airbrush art have bled over to modern day children's crafts.