There are several elements which go into designing fabric which are easy to determine. First, the proper fiber content of the yarn for the project being considered. For instance, you wouldnt necessarily choose a fine silk yarn for a washcloth or rug, or a scratchy synthetic yarn for a delicate blouse fabric.
Secondly, the appropriate sett for the size yarn used or the desired effect wanted in the fabric. Too close and the fabric will be hard, too open and it will be gauzy.
Thirdly, the right beat. Beating too briskly and too hard will result in a hard fabric and if the sett is open enough, a weft faced fabric. Uneven beating will cause streakiness in the fabric.
The right fabric structure is important for the item made from the fabric. Long floats that may get pulled would be inappropriate for baby blankets or outerwear. However, floats are ok for curtain fabric, shawls, scarves and dressy fabrics.
Proper finishing is just as important as the initial design draft. A woven wool fabric almost calls out loud for wet finishing. Linen fabric softens considerably when wet finished. Wet finishing may not be appropriate for rayon fabrics. Some chenilles will...