Originally Posted by MadQuilter

If you use an iron-on interfacing you don't fold the edges under. Instead, it is easiest to transfer the pattern to the paper side of the interfacing, then cut that pattern out a little larger. Press it onto the BACK of the fabric and now cut it on the line. This you press onto the background fabric.

It is important to follow the guidelines for what is ironed first - what is hidden, and you need to pay attention to any pieces that may be mirrored when you trace it.

I use steam-a-seam2 and have not had any problem with it.

My preferred method of securing the seams is to blanket stitch around all the raw edges.

If your applique piece is really big, you can trim the center out of the interfacing and only iron on your outline. That leaves the center piece a little softer and allows for more quilting in the applique.