My sister taught me to smock one afternoon in about an hour. I already knew a little bit about sewing. I could sew in a very basic way. I had sewn for my son and once I had a daughter to sew for, I got even more interested in sewing. My sister kept urging me to learn to smock for this baby girl I had. I had only the vaguest idea of what she was talking about. But after that one hour session, I was hooked.
The first book I purchased to help me in this new needle art endeavor was by Elizabeth Travis Johnson simply entitled, "English Smocking". Ms. Johnson had a list in the book of "Do's and Don'ts" in the planning of a smocked garment. Those tips held me in good stead and to me were the epitome of good taste for dressing a child. For the most part, they are still just as good today and bears a review!!!
From Elizabeth Travis Johnson (paraphrased):
Do make the garment style age and body type appropriate, i.e., a waisted dress is not as good on a one year old as a bishop and a ten year old looks better in the waisted dress.
Keep color shades of brightness in the same family.
Use quality fabric.
Smocking is a busy form of needlework, so use care when adding too many other details.
Keep sleeves short, collars small and hems deep.
I guess it is because this is what I first learned when I was learning to smock,but I still lean towards these ideas today.