Day 1 is the first day of expectation setting.
"Pushing hard" isn't hard if its all they've ever known, its just normal...it just makes them better, happier and exposed to more opportunity. How hard working, successful, energetic will be factors of nurture imho. I'm seeing first hand in NYC how crazy competitive its going to be for that generation...its like 1000x as many people to eat the same 8 slices of pie.
Don't blindly pump sunshine and give blue ribbons for everything, but teach them its okay to fail as long as you tried your hardest and got back up and went after it again and again. Don't let negativity be an influence on their outlook.
Kick out the TV, its a mind-waste. Seriously lock it up except for events like Cowboys games or something. It really is a nasty habit, even with some quality programming out there.
Get their read on! Always be reading!
Get them doing stuff always, all the time (music, languageS, building stuff, figuring things out), not just sitting absorbing garbage.
Expose them to the outdoors as much as possible...and animal life. Different topographies, climates, landscapes, etc.
Expect too much of your kids, chances are they'll deliver.
Don't coddle, don't be their "best friend" be their parent.
Teach them to question authority if it something doesn't add up.
Teach them humility, don't let them be bullies, racists, *****s...even when they are just starting out.
Expose them to knowledge as a way of life...try to build the thirst for understanding into them.
Teach them healthy eating habits...if you can go super low meat or even veggie, more power to you.
All that stuff above is just my belief that more or less we all start out with the same amazing potential...and teaching someone that staying focused on topics for long times, always being active and not just sitting on the couch, watching TV....pumps up their brain. When they are young they can learn so much so fast...its just a great opportunity to help them be exceptional and get ahead in life. I see so many that want to coddle their kids like toys or "let them be children" as it that means anything other than their adult romantic notion of not having responsibility.
Oh and finally, teach them that wearing their hat backwards may incur the unexpected wrath of about a dozen or so people that question their ability to lead others.