What do you tell someone who told you they like you but you don't like them?

Basically, look for variations on "Thanks, but no thanks" -- "Thank you for the compliment," and then change the subject. Or try something like, "I don't know. Not right now. sorry." and then they will forget about it. If they keep pressuring you, be direct and honest. "I'm sorry, but I feel like you're pressuring me and I don't like that."