First ofall congrats to you all.In general every one is nervous about gd and personal interview. Here im giving some general tips for you based on my experiance.
I attended 4 interviews before get in to scms. According to my little experience,
Dont feel it as an interview.
Don't try to lie that is regarding ur hobbies every thing.
Know ur self very clearly, as well as ur surroundings.
Dont feel that panel members are intellegent than u. Here i am not saying they are not intelligents.
Be confident on ur self.
Always keep smile on ur face that will shows positive impact.
Just relax, try hard take it kasy the results.
All the best for ur interviews.