I had a wonderful lesson this week with my student Kevin, and I was reminded of this tip that I learned from Susan Khalje several years ago.
When working with certain woven fabrics, you may notice that the selvages have slight puckering. This is not a defect; it's an artifact of the manufacturing process. The guide threads along the selvages are pulled very tight during the weaving process. When it's rolled off the weaving rollers onto the bolt, you get this result:
To release that tension, and to give you a better, non-puckered surface on which to lay your pattern, simply make small snips along the selvage every couple of inches with a pair of tailors points. The snips only need to be long enough to release the tension. In this case, they are about ¼ inch. I angle my snips out of habit, but you can make them perpendicular to the selvage with similar results.
You can see that the snips relieve the tension and allow my fabric to lay perfectly flat. I didn't press or otherwise flatten the fabric; this is simply a result of releasing the tension from the guide thread.
This only takes a few seconds to do, and it makes life so much better when you are laying out your pattern.
HTH and Happy Sewing!