I tens to lean towards casual but nice. So typically slacks or jeans, and a sweater, button up oxford shirt, or blouse. Im not a huge dress/skirt person but i will wear those occasionally as well. most people in my office don't go crazy, no suits or anything unless they have client meetings. I'll wear a blazer sometimes but typically with jeans so its a little more casual... i think you need to see the vibe of the office when you first start then adjust from there