Interesting question. For "looks like," "seems", and "appears" are very similar and frequently interchanged with one another. I would say that "looks like" is often used for making a prediction when one doesn't have complete information or certainty of an outcome but feel strongly that the prediction/outcome is true based on the available, and observable, information. For example, - It looks like you are unhappy [because you usually are talkative at dinner]. It looks like you are ill [because your nose is red]. It looks like Steve is about to move our of his apartment [because I see stacks of boxes through the window]. It looks like it could rain [because it is cloudy]. I would say that "appears" can be substituted in all of these cases for "looks like" since it also would be used when observing something that may or may not be true. For "seems," this could also be substituted with the above examples: It *seems that* you are...., It *seems like* Steve is about to...., It seems like it could rain. However, "seems" can also be used with feelings. For example: It seems like I always have headaches on Saturday. I would say for this example, only "seems" will work although "It appears like I always have headaches on Saturday." suggests the speaker has consistently had headaches several weeks in a row. Some examples of "look" could be: You look tired. You look ill. He looks foreign. vs. You look like a tired person. You look like you are ill. He looks like a foreigner. By itself, "look" isn't so much a comparison but something that is being asserted as fact. All the others "looks like," "seems," and "appears" have a sense of doubt--lack of certainty. Long answer. Hope this helps.