I would overcast the raw edges
I would measure it
Soak it in hot water until the water cools to room temperature
Gently wash it in the machine in cool to warm water
I use the "dry until done" regular setting (I think there are a couple of people on this board that dry their fabric on the hot/normal setting)
I would measure it again to see if the above had been worth the effort.
I also would use at least 3/8 inch seams
It all ends up being personal preference. I make things to be used - I expect them to need washing - I want them to hold together with minimal puckering and I want the seams to be sound