Sewing lined curtains "These are very simple directions to follow, and for a beginner like me they turned out nice. A tip you might want to try while sewing the lining to the left side of the front panel is construct a temporary pleat in the middle of fabric. I held it in place with pins. It helps keeping the lining flat while sewing. Once I did that it was much easier to keep the seams straight."
How to - lined curtains with ruffles at the top
Pinch-Pleat Panels. For 9′ ceilings and larger windows, you would allow 4″ for returns and a 4″ center overlap. From my 49″ width, I deducted 3″ for each side edge, leaving 43″. 43″ minus 30″ (5 pleats x 6″ each) leaves 13″. 13″ divided by 4 spaces between pleats gives us 3.25″ between pleats.