“Watch” is generally used to refer to an object that is moving, and to an object that takes place over a period of time. Like a football game or a television show. For example:
- Tomorrow I will watch a football game in London.
- Did you watch the new episode of “Doctor Who” last night?
“Look at” is generally used to refer to an object for a shorter period of time, often to observe details. The object is often unmoving. Like a menu or a painting. For example:
- I looked at the menu, but didn’t find anything I wanted.
- While I was at the Smithsonian, I looked at a lot of famous paintings.