The best bit of advice I was given was "think about what works for your lifestyle". Back when I was working a corporate job, I was very much living in pencil skirts, print blouses, cigarette trousers etc. Now I work from home and study, I live in jeans, chinos, shirt dresses and loungewear.
Go through your wardrobe and pull out the clothes that you find yourself turning to - ie skinny jeans and then maybe we can help come up with similar but alternative items. For example, I have 2 pairs of skinny jeans but also have 2 pairs of chinos, one denim midi pencil skirt and one pair of jodhpur leggings which I would wear the same way and with the same things as skinny jeans.
Then look at your tops - are they just plain tshirts? If so, look for tops that are slightly different ie cold shoulder, Bardot. I've just bought a gorgeous tshirt from ASOS that has a lace cut out which makes it slightly more modern than just a standard black cotton tshirt.
I do find A/W is a lot easier to dress for. Just need a couple of nice jumper dresses over tights, decent coat and boots that go with everything. Summer catches a lot of people out. I agree with barefoot that Gap is a good go to place for good, modern basics and they often do outfits which would really suit your lifestyle - ie chinos with vest top and slouchy shirt.