You do not need to wear a uniform to get into Berghain. The bouncers, above all, are looking for interesting people who they believe will add something to the mix rather than just go there to consume and gawk. There really is not much to conform to, other than some contextual awareness of the fact that you're going to a techno venue and there is a certain culture behind that, e.g. flashy logos or ostentatious clothing is generally frowned upon, and you should be dressed comfortably enough to actually rave. Most importantly, I think, you need to give off a vibe of freedom and non judgement, the things going on in Berghain are not for everyone. Elon didn't get in, and frankly it would probably be a buzzkill if he did.