|I know everyone has their own way of tracing off patterns, but I am so happy with my current technique that I thought I would pass it along.
1. Lay out a large piece of foam core board on a table.
2. Unroll Art Kraft paper onto foam core in the size necessary for tracing pattern.
3. Place sheets of 8 1/2x13 1/2 carbon paper (the kind used by offices before photocopies were common) over the kraft paper in a single layer, carbon side down.
4. Place pattern on top of the carbon paper. Pin these layers into place (I use the cruddy pins that I bought before I discovered glass head pins, but you could use pushpins).
5. "Trace" your pattern with something that will not mark or perforate your tissue pattern -- I use the wrong end of my sewing machine's lint brush, but in the past have used a knitting needle among other things. Use your tools for a perfect copy -- french curve, ruler, etc. etc. etc. You will probably have to unpin and reset your papers to get the whole length of a pair of pants, but matching up is really easy.
6. The carbon reproduces your original pattern beautifully but it will smudge. Protect your new copy by spraying it with Krylon Workable Fixatif -- it is the stuff that artists use to preserve pastel and chalk drawings. Your pattern will be perfectly rollable and foldable. This stuff stinks so either use it in a well ventillated room or do it outside.
This method will give you a heavy duty copy of your flimsy tissue pattern.