Custom graphics are a lot of fun.
I've been learning over the past year - pinstriping and airbrushing. It takes much practice.
As others have pointed out there are specific tools (sword stripers in multiple sizes, outliners, lettering brushes, etc.). Paints are important too - one shot is good stuff - you can also get striping and lettering enamel from House of Kolor and other companies. Be warned - the type of paint you use does make a difference - base coats tend not to flow out at all, so make sure you get striping enamel.
There are many ways to go about learning - but grab a brush, some paint
http://www.coastairbrush.com , some metal signs
http://www.rjsign.com/ and go to work!
A book may be helpful as well - Eastwood has a pinstriping how to book that's OK.
- Ryan
