I did my first practice piece (one of the deck tie-downs) and I'm so glad I can throw it away. I marked the fabric with a Sharpie, activated the fabric with acetone, then according to Tom Yost's instructions applied three coats of thinned cement and heat-activated the glue.

There's blue Sharpie ink all over everything. It isn't coming off with isopropanol.

OK, lesson learned quite cheaply. But I don't have the confidence to cut freehand so what do I use to mark up where I'm going to cut? Is the IPA effective as long as I use it right after cutting? Ballpoint? Pencil? Masking tape? I think Tom shows some rough layouts using masking tape but that only works for relatively straight lines.