What kind of compliments are creepy?

I work as a courtesy clerk at my local grocery store. It is a very popular grocery store, and when I work there's always a cute girl, lately, I’ve been starting small conversations with them in line while I bag their food/drinks which I never used to do, I used to be very quiet and my coworkers thought my facial expression looked mad 😂 but I wasn’t mad just had a serious look.

Now I’m always trying to talk to girls. One of my friends seems to be so good at complimenting. I asked him the other day what I do he said do what I do compliment their nails and makeup. But be careful with what u say cause you’ll come off creepy. But I still don’t know what to say. I compliment their shirts cause it's an easy conversation to start, with purses, and hair.

Whenever one of them buys flowers I say to them Oh are those for me when they buy alcohol I say Can we share this.

I’m not the best and compliments or small talk whatever u want to call it. But I’m trying and personally feel like I’m doing good, compared to when I never said anything.

If any of you can tell me if what I’m saying is good or not. And what I should say than doing the same old same old? Also happy Thanksgiving (if u celebrate)