first thing - don't assume that if you have the selvages lined up the fabric is squared. Hold up the fabric folded in half and move the selvages to the left and right until the fold lies straight with no wrinkles. Now the fabric is on the straight of grain. Carefully lay it down. Always cut with the fold towards you. Use the fold as your straight line. From Fons and Porter I learned, to cut the first strip a little wider and then trim it down. After that first cut, you can cut to size. Hold up the fabric and unfold - I bet you won't see the dreaded "V"