Focus on your strengths and weakness.
Juat be yourself and always be honest in giving information.
Be honest and transparent, do not claim what you are not able to deliver.
Ask questions to set your expectations before deciding to accept the offer (in case)
First of all, be confident in your self. Trust your self that you can do it and you'll gonna past the interview. Second, just smile and be jolly. Last, enjoy the interview weather you past or not.