First I use a number 2 pencil and I trace the pattern on the non-sticky side of non-woven fusible interfacing. Leave at least 1/2 inch between patterns. Cut out around the patterns leaving at least 1/4 inch on the outside edges. Pin the interfacing to fabric, sticky side to the right side of the fabric.
Set the sewing machine to a short stitch and use a clear plastic foot, if you have one. Sew on the drawn line using a slow speed. Having a needle-down setting on the machine is handy for this. Trim seams to a bit less than 1/4 inch and clip curves. Then cut a slit in the back of the interfacing, sort of an "X", and turn the applique through to the right side.
Using a pressing sheet and a small iron (if you have it--if not just use the tip of the iron). Press the edges only (leaving the center sticky stuff for attaching the applique to the background later.)