For toiletries, I have got a few 'multitasking' things. Eve Lom cleanser, which comes in a small travel sized pot. It just needs a cloth to take it off, so I use the hotel flannels to save having to take a cloth. Removes the need for taking eye make up remover, toner, cotton wool etc
You can leave it on for longer to work as a mask as well!
Elemis marine cream moisturiser which removes the need for eye cream
I've got a little bottles of my favourite shampoo and conditioner which I take if I don't know if the hotel has freebies, but if I'm going to a hotel that provides it, I don't bother.
I've got a dedicated make up bag which has got my things that are running out. So when a mascara, foundation etc gets towards the end of its life, it goes into the travel kit. Partly so it's no great loss if I lose it/leave it on a plane, and partly because they are tried and tested, so I'm not going to be stuck away with a foundation that is slightly the wrong colour and no means of getting to a shop for a repalcement.
Clothes: Wool doesn't crease, or the creases don't show. Dresses with sleeves plus a scarf look smart enough to not need a jacket on top.
Don't know what your style is, but I like M&S, Hobbs and Uniqlo for work dresses.
I have a pair of stunt shoes in a neutral beige/brown which have a mid heel and are really comfy. They are the only shoes I bring with me
Gym stuff: I've got black Nike trainers which double up as casual shoes to wear out in the evenings, then I've got leggings and tops that I can wear twice without them stinking but which will wash really easily in the shower and dry very quickly if I'm going to have more than 2 workouts.
1 or 2 pairs of black jeans, a couple of neutral tops and cardigans and some floaty scarfs, and I'm good for a week away.