Here is a thought - if you don't prewash, a lot of it is not applicable, because the fabric is going to shrink differently and change shape once it's washed. I've yet to find a layer cake that ends up square after washing, it always shrinks more one way than the other, usually like 9.5 x 9.25 when it started out at 10"
I have no problem stretching a tiny amount, lie 1/16" inch, and maybe up to 1/8" on longer pieces (like over 6") More than that, I'll skimp on a seam allowance rather than stretch the fabric right to the edge.
I don't use steam when pressing, but if I've got something really wrinkled, I might mist it a bit to help with that. I also don't use starch and don't like working with fabric that has been stiffened. I participate in some exchanges, and when I get fabric that has been stiffened, I really want to wash it to loosen it up before I use it (I don't) and each time I use it, it reminds me how much I don't like working with stiffened fabric.
If you want to get good dealing with bias, then start sewing easy curves and shapes that require bias. (which means no starch as you need that stretch). Or sew up some tops or lounge pants using knits. Learn how to adjust the settings on your machine so it does feed well without pulling or twisting.