"To look at [some thing]" means to specifically pay attention to that thing.
"To look to [some thing]" has various meanings, but in this context it means to look in the direction of that thing.
So if I say I'm looking at the parking lot, I mean that the parking lot itself is my focus. However if I just look to the parking lot, I'm just looking over toward that area with no special focus.
She's looking at the sky (There's something in the sky that has attracted her interest)
She's looking to the sky (She's looking generally upwards with no particular focus)
As a side note, to look to a person has a different meaning, "to hope or expect to get help, advice, etc. from someone":
I look to you to take care of the kids while I'm away.
Mary looks to Tom to cook their meals since she's been sick.
Edit: In a recent comment I wrote:
".. traders who deal in Netflix stock primarily look to subscriber statistics to determine whether they will buy or sell."
I used to rather than at, partly because I was still thinking about this question, but also to imply that the statistics aren't the only thing the traders look at -- they look at the statistics and other related data.