1/ LOOK FOR Look for is used, in general, when you need to find something or someone: Examples: Excuse me! I’m looking for the manager’s office. Do you know where it is? I’ve been looking for a job for months. 2/ SEARCH Search is used when you look somewhere carefully, because you want to find something: Examples: The police searched the house for evidence. I searched the whole room, but I couldn’t find my watch anywhere. You can also search for something: We searched for a sunny spot for our picnic. 3/ SEEK Seek is not used when talking about physical objects. It refers to the process of trying to get something: Examples: Thousands are seeking asylum in Germany. I think you’ll need to seek help. 2/ FIND Find is to get or achieve what you have been looking for/searching/seeking: Examples: You won't believe where I found Jamie. (Finding after looking for) I found a some pair of jeans in a very good condition in Walmart. (Finding after searching) Poor little Adam finally found some peace after saving him from his abusive parents. (Finding after seeking).

Saika gave a great answer. Those words all mean something similar, but each action is more intense than the last. Looking is usually casual and brief. Searching is done with more deliberate methods and more time. Seeking is something that only ends when you die or when you find. You can play the game called, "Hide and Go Seek". When you seek for your opponent, the game is not over until they are found, or until you give up.

As a native, this is my take: To find refers when you completed your search or quest, you already have the object that you were looking for. Even though there are slight technical differences between the remaining three, they can usually be used interchangeably.