Mom's of 2 or more kids...

I have a 2 year old, and we're ttc by Spring 2015. By the time the baby comes my son will be almost 3.5. My question is, how do you all do it? Like daily schedules and balancing things out? My son is really great with babies, even at this age, but he is really whiney and I understand that he's an only child, but will that change too? But how do y'all handle more than one?