Don't listen to GoddessDivine.
If this is going to be a group interview, you would want to stand out. Since this is retail, you'll want to be out-going and overly assertive, but not rude. Smile and be friendly.
There will be questions related to customer service.
"If a customer asked you for help, what would you do?"
"Describe how you would handle a customer's complaint."
And there may be questions to sell a certain product.
When my cousin did a group interview for bath and body works, the interviewer told each of them to pull an item and then sell it to her.
Everyone grabbed smaller things that were easier to sell. My cousin grabbed the biggest gift basket full of items. She got the job.
It's okay to laugh and to be yourself. However, if "yourself" is shy and non-responsive and timid, then don't be yourself. Act like you are out-going.
When I got an interview to get into the xray program, the counselor saw that I was timid and shy. She told me straight up, "If you are shy, act like you aren't. It's 20 mins. Act like you are out-going. Smile. Laugh. It's going to be you and ten people in one room shooting questions at you one by one. They want to see how you deal under pressure."