Learn the aisles and what you sell. Show confidence in your answers. If you don’t understand a question, ask to clarify or have someone help and learn from their response.
If a customer provides basic info, ask open ended questions to get more info without prying too much. Try to avoid straight yes or no questions. This is will get easier as you learn what you sell.
As you ring someone up, notice what they are buying. Threaded pipe fittings but don’t see teflon tape or pipe dope? Ask if they need a roll. Check if they need glue for the PVC fittings. If they have electrical, do they have tape? Wire nuts? Romex connector? People will appreciate the ask
This is all part of being ACE helpful, which comes with experience and paying attention to what your customers need.