I use a piece of glass to practice on. Popular things to play on are plexi, bowling pins, sheetmetal, ect. Glass gives you an advantage if youve never done it before, because you can lay out a grid on the glass (or under it) and practice not only pulling lines, but getting your design symetrical. Stablio pencils are good for laying out a grid, because you can stripe over it, and then wipe the rest away without damaging your design. For more info check out
www.thehamb.com you should find some tips, and other links there.