(Top, culottes and sandals: Topshop; Waistcoat: ASOS; Bag: Sophie Hulme; Belt: From Boohoo jacket; Watch: Michael Kors; Jewellery: Thomas Sabo)
Of the variety of style saviours to have in one's arsenal, I strongly suggest that you add a long waistcoat to the list. It covers (quite literally) all manner of sins and solves the problem of not wanting a jacket in summer but not wanting to be too exposed. You just feel more put together in one. Plus with long sleeves it'll last well into next season.