Since no one saw fit to attempt to actually answer your question (don't you just hate when people feel the need to give you their opinion rather than answer your question), I came up with something: Talk to him
all the time. There was an article a while ago here (or maybe reddit) that studied the amount of words a child hears before certain age between lower, middle and upper class groups. The difference was massive. Upper class children heard a huge amount more words by a certain age (I don't remember the exact range, I'm guessing in the hundreds of thousands). This difference showed up in much improved language skills for the upper class child.
Anecdotally, I've noticed this first hand. On my commute to work I've noticed how different classes interact with their children (as approximated by race). Black and Hispanic parents tend to give some distraction to the child so they don't bother the parent, or are themselves distracted by a cellphone thus ignoring the child. While white and Indian parents (likely middle to upper class by context) tend to constantly interact with the child, asking questions, speaking in complete sentences, etc. Just always having a conversation with them. The differences were stark.
Another idea I picked up recently was to constantly attempt to give your child age-appropriate decisions to make. This will train them to be able to weigh options and decide on the best course of action for themselves. The example I heard was when you're at the store, give the kid the option to buy two snacks--absolutely anything they want. But just two. This may help them develop decision making skills.
One more idea is to attempt to train their ability to delay gratification. You may have heard of the "marshmallow experiment" (http://en.wikipedia.org/wiki/Stanford_marshmallow_experiment) where a child's ability to delay gratification as a young child was correlated with their "success" as adults. Try to run the marshmallow experiment in your home as a standard course. Let him have a bigger payoff if he can show self control for some period of time: food, learning, whatever it may be.
Good luck with your future genius!