Là hoặc giặt trước miếng vải.

Given the above summary, write a detailed text in English for it.
If your fabric is prone to shrinking, you'll be thankful you did. Do this well before you start sewing -- the fabric needs to be completely dry.  Follow the washing instructions for that specific fabric. Whether it's machine wash, hand wash, or hang dry, the instructions should be followed. If you throw your fabric in the dryer and it comes out a little wrinkly, iron it. It'll be much easier to work with when you're sewing.