I found out that using a dinner plate to draw the rounded edge on any large itme that you want to give a curve to is perfect. I was going nuts with a tulle wedding veil and used the plate to be a guide when I rounded the corners with my rotary cutter.
And if you use the same plate on all corners... they are all the same. I used a glass and "ground" it into the fleece to leave marks so I could get a bunch of 3"round circles. I found that if you dip the glass or other "marker" in ground chalk it can leave a chalk mark behind!
I often use a "box" to make a template for pockets.. I have used shoeboxes (kiddie size) and CD cases and VCR cases, too! I use business cards to space buttonholes and even used my DH's cross cut saw to get a LONG ragged edge!