Cotton Poplin

Poplin is a plain weave with a slight imbalance — more, finer threads running the warp than the weft — which gives it that faint crosswise rib you can feel more than see. It's crisp without being stiff, presses to a sharp edge, and holds a gathered ruffle or a topstitched seam beautifully. This is the fabric behind most of the button-up shirts you own.

It's one of the most forgiving fabrics I sew with, which is exactly why I keep recommending it to anyone starting out. It doesn't shift much on the cutting table, it doesn't fray badly, and it takes a French seam or a flat-felled seam cleanly. The only real downside is that cheaper poplin can go a bit papery and lose its crispness after a few washes — worth spending slightly more for a good mid-weight quilting or shirting poplin if you want the garment to still look sharp a year in.

I always pre-wash mine. Cotton shrinks, and finding that out after you've already cut and sewn a garment is a genuinely bad afternoon.