I use a stencil...I design a fin I like... draw in on heavy weight paper, cut it out, then, lightly airbrush it with tranparent paint on the bait but, hit the outside edges a little heavier ...this gives the transparent look ....then, do some shadowing to give it dept. Then get a extra fine paint pen and draw in the fin lines.. there you have it ...a fish fin.....Hope this helps. MuskyRuss