Always go on learning the right postures and gestures.
Take care of your sitting position [or] standing position and also your hands.
Do you know how to use your contact with your eyes?
Don't stare and speak with your eyes meeting the interviewing official.
Do start your interview with the proper greeting ,
suitable/apt and with a smile on your lips and eyes.
If asked to take your seat don't pull the chair fast,by making it sound.
Do it such a way that you know how to handle a particular thing,
in public and specially at the interview.
Clean your face, wear apt dress, keep your finger and toes. [trimmed].
Don't stand [or] sit very close [or] near the official interviewing.
Take care of your look and appearance
Don't look gaudy, don't look like the fallen socks.
Look young active and bright.
For the first impression is the best impression.
You are going to succeed and win in your interview with your good luck.