Why my daughter blink excessively?

I think it's all in her mind. She used to clear her throat all the time, the sound is so annoying. And I know she didn't have any throat problem because I checked with the doctor. She had a strep throat test, it came out negative. I told her to stop clearing her throat all the time.....then she did - but now she switched to blinking her eyes all the time (excessively). It's even more annoying because it's hard to watch her. She's like from this mental institution who have abnormality or person who have problems. Her reason is that she have no control over it. I know she's just too conscious about herself and she starts doing this mannerism on her body. How can I help her, I bought her those eye drops to lubricate her eyes but still the same. She's a very uptight and cautious girl, even her teacher would tell me the same thing. How can I help her?