First, study smart people. Find the real smarty-smart smarts, the big thinkers, the visionaries. Note how often these people talk about their own intelligence. Copy them.
Do something. Solve a problem. Invent a new thing. Create something beautiful. Basically, put your head down, work hard, and in a few years or decades, people might begin to believe you are smart. Alas, it is true that by the time this happens, you may no longer care what other people think.
Take a test and then just move on with your life, especially if it’s a test administered by doctors to determine if you know what year it is and what an elephant looks like.
While we’re talking tests, don’t let anyone else take tests for you. This is called cheating and it will not make you seem smart, though an awful lot of people seem to believe it might.
While we’re talking tests, don’t ever say something like, “if we stopped testing right now, we’d have very few cases if any.” Just as a hypothetical example, of course.
Read a book. This is the sort of thing smart people do even when no one is looking. Remember that reading a book is not the same thing as holding a book and pointing at it. I know you know this because you’re super smart and all, but just in case you were wondering.
Never, under any circumstances, refer to yourself as a “very stable genius.”
Admit when you don’t know something. This is a tricky one, because it seems counterintuitive to prove your smartness by confessing that you don’t have all the answers. Remember, no one can know everything and all the smartest people are really quite comfortable with this. Feel free to say things like, “I don’t know, but my friend Anthony is really smart about this stuff, so let’s just let him talk.”
Stop talking. Really, I mean it. Hush. Be quiet. Shhhh.