A top can swallow a whole outfit without anyone being able to say why. It usually comes down to volume in more than one place at the same time.
Volume in one place only
If the sleeve is full, keep the body close. If the body is relaxed, crop it or tuck it. Full sleeve plus long body plus wide trouser is three decisions fighting each other.
Where the shoulder sits
The shoulder seam should land on your shoulder bone. When it drops past, the whole top slides down with it and the neckline follows. A dropped shoulder can look great, but only when it is designed that way, not when it is simply too big.
The shoulder seam should land on your shoulder bone.
Length and the half tuck
Our knits are cut shorter so a half tuck looks deliberate instead of bunched. If a top is long, tuck the front only and leave the back out, which keeps the waist visible without adding bulk at the hip.
Fabric weight
Heavier knits hold their shape and skim. Thin, clingy fabrics show everything underneath and tend to pull across the chest. If you love a thin fabric, size up and let it hang.
Layering
Keep the layer closest to you the most fitted and add volume outwards. A rib tank, then a relaxed knit, then a structured blazer reads as considered. Reverse that order and it reads as borrowed.
