yea as stated above you need a steady hand and need to get it down in one shot what i do is find a childs ball.. i know it sounds silly but give it a shot

get a heat gun and some pin striping from the local parts store grab the ball between your knees and have someone help you with the heat gun slowly start to run it varying the amount of heat used make curves S shapes anything you can think of as a test for what and how your gonna do it later with a bit of practice you can lay it down super easy and the heat will actually make the glue adhere a bit better

its fun to me i love doing this kind of stuff i use pin striping from the parts store on lexan car car bodies to do flame jobs and such .. with them the only difference is the tightness of the turns and crevices and the body needs a cold cloth touching the back of it to keep it from warping in the heat.. works great try it youll find its a sure way to get the hang of it all