Can you say "if I were you"? Is it correct? (Please pay attention to the corrections.) Yes, it is correct. You're talking about an imaginary situation.

Your question should be 'Is it correct?' And the answer is : yes, it is. You could say, for example: 'If I were you, I'd get a new job.' 'If I were you, I wouldn't buy that car.' 'If I were you, I'd go to the doctor's.' You use this mainly to give advice to someone - to say what you think they should do.

Yes it is correct.

Definitely. This structure (clause) is used to introduce a conditional sentence (type II). "If I were you, I would go to the cinema".