When I was younger I used to wear granny type cardigans in a cool ironic way, I still love this look but just look mumsy and frumpy in them now. Since becoming a Mum I am very concerned about looking Mumsy.
Some bob style haircuts are on seriously dangerous territory too. A well cut bob is about the chicest haircut you can have, but these days tends to need a bit of graduation or at least some choppiness. But a slightly too long or grown out one with the wrong kind of blunt fringe, and tucked behind the ear, just makes me feel depressed. 99% of them if they just had an inch chopped off it would look 100% better.
I know I know, easier said than done to get to the hairdresser if young children and particularly if also working etc which is precicely WHY it looks mumsy.
Floral prints unless they're ironic. Bob haircuts of any kind. Jeans or trousers with pleats in the front. And those horrible 'Mom' Jeans, tapered jeans, jeans that don't fit properly at the top of the thigh. Shapeless/square t-shirts with loose, flappy sleeves, unless gardening, cleaning gutters, cleaning the oven, painting, etc. Mary Jane shoes (unless ironic) or sandals like this. Culottes. Women's Speedo-type swimwear.