"To Believe your own thought, to believe that what is true for you in your private heart is true for all men,----- that is genius".
Emerson believes that all men should think for themselves and be individualistic. He hates the effect that society has on everyone with the social norms that it creates. This quote is saying not to let society influence you think what you want to think. In Emerson's opinion the smartest person is the one who thinks for themselves and isn't influenced by trends. If everyone in the world followed social norms then everyone would look the same and do the same things. There would be no variations in life.
"He walks abreast with his days, and feels no shame in not 'studying a profession' for he does not postpone his life but lives already."
Emerson despised education he thought that it wasn't worth going to college. He believed the most successful person will be the one who trys everything and does what he wants to do. If everyone followed this idea today college might not exist since no one would be going to it. Also people jobs may be easier to get as a lot of them wouldn't require a college degree anymore. It would be very different to think about a society in which no one goes to college as most everyone does today.
"A man must consider what a blindman's- buff is this game of conformity"
Emerson hated the social norms and thought that people had to be one with nature. He believed people naturally we're supposed to be whoever they wanted to be in life. If everyone was naturally who they wanted to be in life their would be much more variations in the world. Some people today still aren't who they want to be due to being worried they won't be accepted by others. In a world where everyone is themselves things would be much different than they are today.