The first cotton skirt I owned was a flat, stiff thing from a supermarket rail, the sort that stood away from your legs like it had its own opinion about personal space. It taught me that cotton on its own, with no stretch and no lining, will crease the second you sit down and hold that crease for the rest of the day.
That's really the honest limit of the fabric. A heavier cotton skirt is brilliant for structure but it is not forgiving if you're moving around a lot, sitting cross legged, getting in and out of a car repeatedly. It also isn't the one to reach for on a properly cold day unless you're layering under it, because cotton has no warmth of its own, it just sits there looking neat while your legs disagree. Light cotton, the almost see through kind, is the wrong choice for anything fitted or pale unless you know what's underneath it, a slip or a layer, because daylight will find every seam and every shadow.
Colour wise, I've had the best run with anything in the mid tones, a rust, an olive, a proper denim blue. White looks wonderful on the hanger and then meets a kerb puddle within the hour. Black cotton fades fastest of all the darks, it goes grey at the hem within a season if it's in regular wash rotation, so if you want a dark skirt that still looks dark in a year, go for a very deep navy instead, it hides the fading far better.
As for how it wears, cotton softens properly over months, which I like, the first wear always feels a bit like cardboard and by the tenth it's folding where your body actually bends. The trade off is that it also loosens at the waistband faster than you'd expect, especially an elasticated one, so don't buy it too snug on day one expecting it to stay that way. Wash it cooler than the label's upper limit if you want the colour to last, and skip the tumble dryer entirely if there's any pleating or gathering, heat flattens that detail permanently and no amount of ironing brings it back.
On the coverage side, a longer cotton skirt generally does its own work. Sitting down test, fine, it doesn't ride up the way some synthetic ones do. Windy day is the one to watch, a straight cotton skirt with no weight to it can lift more than you'd like, so a slightly heavier weave earns its stripes there.
The one mistake worth avoiding is buying a pale or lightweight cotton skirt without checking it against bright daylight first, in a shop with proper lighting, not the dim changing room bulb that flatters everything and tells you nothing.