As we speak (type), I have finished exactly four-- count them!-- Aunt Millie's Garden blocks. The first I finished in summer 2010. The second was finished sometime between then and now; I'm unable to pin a timeframe on that one because I never even took pictures of it until now. The third and fourth were finished two weeks ago and last week, respectively.
The vinyl overlay method has been slow but much less tedious than using freezer paper or hard plastic templates. I don't follow this exact process, but at least that link gives you some idea of how I applique.
1. Less seam allowance is more. It's scary to trim a scant seam allowance when doing applique because one slip and you've wrecked your piece. Also, fraying is a concern. However, I've found that smooth curves are easier to create with less seam allowance, and there is also typically less fraying because you have less fabric you are trying to turn under.
2. Use the lightest marking pencil tint possible. Early on I used a black marking pencil. The line markings are just visible on the edges of those pieces, and it makes all the applique look very dirty around the edges. Currently, my tint of choice is pink. It is working out really well.
3. Pulling stitches too tightly makes them more visible. At times, when we tighten our hand stitches they disappear into the fabric. During the course of this project, I've noticed that sometimes tightening stitches makes them more visible, rather than less. Take care not to pull too tightly, otherwise you will get a ruffly edge around your piece, and the finished product will not be as smooth as you'd like.
4. Using a light box to trace is much more helpful than tracing on the window or using the television. I recently purchased one for myself. More details coming soon.
5. Trimming and snipping leads to crisper points. Points, of course, suck. Ugly points suck even more. It has been much easier to create satisfactory points by trimming and snipping at the vertices, then folding and tucking. I snip right up to the point, just a few threads from the fold line. Then, I tuck and fold the seam allowance in, trimming extra where necessary. If I had five hands I could take a video or pictures and show you.
6. Sew right to left. I am right-handed, and sewing right to left makes it much easier for me to turn and sew, turn and sew. Perhaps southpaws should sew in the opposite direction?
7. One thread does not fit all. There is not a universal color that will work with all fabrics-- if the thread does not disappear just right against the fabric, then the stitches are visible and that is crazy-making. And before you tell me to try that invisible thread stuff, know this: it is impossible to get a good knot with invisible thread.