I can't really help you with making templates as I have a few bought ones that I use again and again. However, I have used some things lying round the house for quilting 'stencils', for example, my kids have plastic cutters for when they do play doh in the shapes of hearts, stars, flowers etc and I've drawn round them before now! (Wash the play doh off first! :D ) Or you can use the edge of a plate for curves. I also have a draftsman's flexicurve (from when I did a garden design course yonks ago!) and that is useful for making continous waves. So really my tip was to look round for things that are nice shapes that you can draw around!
K x