I look at you = I point my eyes in your direction.
I look to you = I am relying on you (for or to do something).
When I look at you, I feel very happy and I can see that you are beautiful!
I look at you every day, and you get more beautiful every day!
I look (or I'm looking) to you to keep control of the people at the party.
I always look to my brother when I need advice about computers.
Interested in Language