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. This is why it is important to wet sand the metal first. A base coat should be applied to the metal before any airbrush art design is started. A damages needle can be disastrous to your ability to create high quality art, because if you are unable to straighten a bent needle back out or the needle should break completely you will not be able to finish your airbrush art until you can get a replacement. If you do end up bending your needle you can try and straighten it with either pliers. Then go from there and start drawing out how you would have made it look. Once you are happy with it then airbrush it on to your project to create your own unique airbrush art design. If you don't want to get outdoors to look at new scenery and you don't want to go to the library then you can just surf the web. When choosing an airbrush compressor keep in mind that put airbrush art onto t-shirts does require a high psi. The psi setting should be between 40 to 60. Make sure that your compressor is rated for the type of work you are going to be doing. In this case it will be airbrushing t-shirts. When doing airbrush art onto t-shirts as a business then invest in a commercial air compressor. When working with nails you do not want to end up airbrushing the person's fingers. So before attempting to do airbrush art on nails gain some experience with airbrushing on larger surfaces. Depending on the type of airbrush art you are doing will determine the type of airbrush that you need. When doing airbrush art on nails go with either the Iwata HP-A or the Iwata HP-B. If this should be come damaged then you could have serious problems with your airbrush. Don't worry though it is not hard to replace these parts should there be any damage. Your airbrush will have a handle on which you can hold onto the airbrush with. Airbrush models come with either a solid handle or a handle with an opening.