My first chiffon skirt was a two-layer thing in a sale bin, no lining of its own, and I wore it once before realising every pair of eyes behind me could see exactly what colour knickers I had on. The lesson was simple: chiffon is not a fabric, it is a fabric plus a decision about what goes underneath it.
Getting the fit right with chiffon skirts is less about the waistband and more about the layers working together. The outer fabric has almost no structure on its own, it floats, so most of the actual shape comes from the lining or slip underneath, and that needs to sit properly at your natural waist or hip without bunching, because any lumps under sheer fabric show through in daylight the way they never do in a changing room with flattering lighting. Check the waistband itself too, elastic ones can dig if the skirt is heavier with layers than it looks, and a fitted waistband on something this light sometimes gapes because there's no weight pulling it down to hold its place. Length matters more than usual as well, since chiffon moves with every step and a hem that looked midi standing still can swing up noticeably higher when you walk, so if you can, actually walk around the shop rather than just stand at the mirror admiring yourself.
I'd be honest that chiffon skirts are a poor choice anywhere you need to move fast or get low. Cycling, anything with stairs in a gust of wind, a garden with brambles or a dog that jumps up, all of it. The fabric snags easily, it doesn't forgive a rough handbag strap or a rogue zip from another garment in the wash, and it creases if you sit on it for a long car journey, then needs steam or a very patient iron to recover. It's also not the one to reach for on a properly wet day unless you enjoy it clinging to your tights like clingfilm.
As for what to avoid pairing it with, skip anything else floaty or sheer on top, because two soft fabrics together just collapse into a shapeless blur with no definition anywhere. Heavy chunky boots can look wrong too, dragging the whole thing down when the point of the skirt is that it barely weighs anything at all.
Would I actually wear this on the day I'm imagining, or am I just in love with how it moves on the hanger?