Practicing on a string bean comes from the Francis books. Francis' little sister mostly eats baby food until she can eat regular food, but in the mean time, she eats string beans to get in shape for it.
My practicing on a string bean involves making knitted, embroidered, or quilted things for practice. So, if somebody asks, "Can you make something like this thing?" I can show them examples or know I know enough to do it without having practiced first.
This page is my huge list of things to learn, although it isn't complete yet. Sometimes I know what I should learn and do not know the steps to get there yet.
As far as quilting is concerned, the beginner quilting skills I listed in the page are not the things beginner quilters learn to do all at once, but they are the most common techniques quilters use and form the basis for all quilts. I also listed some common quilt top patterns, including tumblers, diamonds (done!), half-square triangles, pyramids, hexagons, baby blocks, apple core, clamshell, and squares (about 1/3 the way done), jelly roll, rag, crazy (combined with embroidery practice), and cathedral window (in planning mode). I will study each one, design the quilt according to common variations on the pattern, and make the quilt so it obviously the pattern and stands out a little.
The embroidery stitches are all the basic stitches and their less basic variations, along with some fillers from Needle 'n' Thread. However, because I like Chinese embroidery, I have included stitches from a Chinese embroidery book Mom and Dad got me for Easter. I am not studying Chinese embroidery, but think the stitches could be used in other embroideries. To become vaguely familiar with embroidery embellishment techniques, I will also learn beading, couching, applique (combined with quilting), goldwork, and ribbons. For things technically different than embroidery, but very closely related, I will practice crewel, whitework (cutwork, drawn thread) counted thread (specifically needlepoint, cross stitch, and chicken scratch, the first two because I should and the third because it is pretty), and within specific embroidery traditions, I will learn Ecclesiastical, Jacobean, and blackwork embroidery, because I am a nerd. Jacobean and crewel will probably combine, but not all crewel is Jacobean and vice-versa.
For now, knitting is not as important as quilting and embroidery, and I will probably have to practice on toys or clothing because I am not comfortable making my own patterns or adapting other people's yet.
I have a feeling art will be extremely helpful, but I do not know why yet. Just in case, I am learning drawing, watercolors, and photography. Drawing will obviously be useful for making my own embroidery or applique patterns and quilting templates, and photography for item listings, but there are probably far more reasons to learn art. I might figure it out eventually.
Interior design will help me understand how and why people decorate, and how I can make items that would work well in people's homes.
Sewing is the least urgent, but will help me learn more about how fabric and sewing works in general, which might give ideas on how to make quilts more interesting or unique. It will also improve some items in the shop like towels and let me add some new kinds of items to the shop.
Whenever possible, the stuff made for practice is posted in the shop, like with this embroidery sampler. That seems to work best for embroideries, maybe because it is so easy and quick to undo mistakes and redo it the right way, compared to how long that takes for knitting and quilting.
Hopefully sometime in the next five years after all this work, I can be a certified master knitter, quilter, and embroiderer.