There is nothing wrong in using plain "looking" as the action, just follow it up with why and and with what emotions. Unless you explicitly want to focus on the way a character is looking, its best not to bring up looking at all.
1. He ran into Emma last week, in the elevator, she looked beautiful.
2. He ran into Emma last week, he looked at her, she was beautiful.
(in the 2nd case, is it not obvious, that he looked at her. Do we really need to emphasis on that he looked. How else would he know she was beautiful?)
Yet if you still desire to have other options read on.
Your characters don't always have to "look". The process of their eyes falling on someone/something, can be many things other than "looking".
Consider these examples
-he can ogle at someone/ an object
-have a blank look towards the object(seeing not noticing)
-eyeball an object
-he can fall in a trance at seeing a girl
-his eyes can get hypnotized (not literally)
-something/ someone can enter his field of view while looking at something else.
-He can "chance" on something accidentally.
All the best writing :)