Before washing, I will run a zig-zag on each cut end of the fabric so that you don't get all of those strings tangling up the fabric.
The main point about "pre-washing" is to get the fabric wet and into a hot dryer. It is the heat that makes it shrink. Having said that, I will wash with a gentle cycle, in hot water and a little bit of soap (because that is often when the fabric will bleed with soap) and the darker the fabric the more color catchers I will put in the wash (2-3 if the fabric is really dark like black).
I then put it in a hot dryer and pull it out as soon as it is dried.
I fold it the length of the fabric in half and then in half again, and then make the first fold down about 12 inches and keep folding over itself until is completely folded up. I like to do it this way, as you can unfold what you need without having to unfold the whole role of fabric each time. Put another way, if you have 3 yards of fabric, but you only need 1 yard, I just unroll one yard, cut it and the fabric that is left is still folded up. Before I started doing it this way, I would have to unfold the fabric and then just leave a big pile of fabric that I need to refold when the project was done. With a big project I would have a haystack to refold.