when I am appliquing several pieces that have to line up, I use a thick plastic vinyl that I purchased at joanns, its 14 gage and 48" wide sells by the yard. I lay it over the pattern and trace with a thin sharpie. Then when I need to add another piece to applique I lay the vinyl over the quilt and can then slide the new piece to be appliqued into the correct place. I do not pin all at once and often use Elmers washable stick glue to aid with keeping pieces in place if I have a pin in the way of my sewing.