1)Empty Glass bottles - as many u can..!
2) Glass liner -black preferably
3)glass colours - based on ur taste..!
the procedure is simple.just thought an image which will give a sharp colorful expression and mark on glass bottle with sketch pen/marker.(as pencil/pen will not work on glass surface).or u can take help of carbon paper to sketch.
after that mark with glass liner on the sketch outline.fill the colors as per ur expression...!
Backlit with White light high lights all ur work..
Just check the photos here...