sharp eyes

bellaphoto

when i search online for childrens photography websites (which i am interessted in ) i see how clearly the eyes are and how sharp they are focused in, even in black and white! i love the look, how do i get that to happen! i own a D40 Nikon, how can i take outdoor photographs of kids and toddlers and focus in on the eyes like that. so sharp and clear. is there a special lens they use, technique???
thanks
:wink

romina