CarolynMT

I prewash everything, it removes the sizing in the fabric (which is a preservative to keep the fabrics from getting insects/mold when in stores) It also preshrinks cotton.

I use cold water, regular wash cycle. My mother (a seamstress for centuries) taught me to always "pre" the fabric you are using as you would after you are done. If you plan to wash something in the washer on regular cycle in the future, prewash it the same way.

I use 1/2cup of white distilled vinegar to set the dyes. I am a cheapskate when it comes to some things

if you look at fabric dyes, they tell ya to add the vinegar to set the dye. So when I prewash, I use vinegar to set dye. Simple and very cheap. Dry as usual in dryer.

The starch after drying prior to cutting reduces the fraying of the fabric when cutting/handling pieces. It also gives the fabric a "nap" to help with nesting seams on piecing. I have also heard (not 100% it is true) that starch creates almost a barrier between any marking pens and the fabric, thereby allowing the marks to be washed out easier (less chance of the marking pen staining)

my 2 cents