There is no rule nor any formula that you might apply on. But there are some tips that might help you:
Do not boast - Be real and righteous, you should reflect the person what you have described in the resume. What you truly know and have interests in, you should mention that only. Don’t do anything just to increase the number of pages.
Acceptable attitude - Attitude has a major role in defining one’s personality. For example - an HR would always expect you to not sit without his permission, you shouldn’t shake legs, excuse yourself after sneezing or coughing, interact with him and maintain an eye contact.
Appearance - Getting ready right for an interview is a must. A formal Code of Conduct should be followed. One should be dressed up properly, nails should be clean, clothes are to be ironed, you must smell good, shoes must be polished, hair must be done in a proper manner.
Be in time - Punctuality matters. Even if your interview starts at 9 try to reach the place before time. That leaves a good impression.
Try not to be over smart - The person sitting in front of you is way more knowledgeable and experienced, so try not to behave in such a manner that may make you look a fool.
Be calm - It is right, that you may develop cold feet but try remain composed. This will help in not making mistakes and better establishment of you.
Be communicative - HR round is all about communication, the person wants to see, how well you can establish your point, how good you are at communicating and expressing your ideas, you know but how well you can explain to others.