In terms of Edinburgh clubs:
Cav aka Lava Ignite (Bruntsfield): You can literally get in here as a guy in a t-shirt, jeans, and any shoes really. But the place is an absolute cesspool, the girls are slags, but hideous ones sadly.
Why Not?: Aside from the obvious joke (She's 14, that's Why Not.) You can get in with non-torn jeans, and a polo or dress shirt, though you can get away with a good t-shirt (if one believes there is such a thing) but absolutely no trainers. For girls anything goes
Opal Lounge, Shanghai, and Po Na Na: A button down or polo, dress shoes, and non-torn jeans or trousers. Though give Shanghai a miss, as it is absolute rubbish the majority of the time. Opal is quality banter and Po Na Na is the best for a top lash night, and has the best totty of either sex.