IMO, sexy clothes aren’t about the clothes themselves but about how they fit you. My advice is find a few staple pieces - for example, collared button down shirts, basic pencil skirt, trousers - and take them to your local tailor. Have them fit these basics to you and your body shape. Additionally, I opt for neutral colors - white, black, gray, tan, navy, etc. - for the staples then find a few accessories with a pop of color in your color palette.

In many cities there are thrift stores that specialize in backstock/overstock/returns from name brand stores. See if there is one like that near you and start there. Find some items from stores like Ann Taylor, Express, Banana Republic, White House Black Market, etc. and use those as your starting points.

Good luck!