GREAT QUESTION… and I'll be using your "they'd go to a museum" in my sales training.
My answer: Change your entire thought process when greeting a client. Instead of thinking about selling. Think about making a friend. Questions are great, but often, you can just make a statement. One of the very best resources for training and understanding this whole attitude and sales approach is Jeffrey Gitomer's book, Customer Satisfaction is Worthless, Customer Loyalty
is Priceless.
With the above in mind, remember one of the basics of sales. Never ask a question that you won't like the answer to. One of the best ways to get around the "I'm just looking" answer is to ask open ended questions. Those are questions they can't simple give you a yes or no answer, but questions that allow you to get more information from the prospect.
Don't ask.
Can I help you? - No, just looking.
What are you looking for? - I'm just looking.
Ask
Pet - What kind of dog do you have?
Wine - That's a very dry Chardonnay.
Hardware - That mower is rated "Best Buy" by Consumer Reports
Maternity - When are you due?
Gift Shop - Are you already collecting Studio 54?
Children's Clothing - That line wears forever.
TMS at trade shows - What kind of store do you have?
Where's your store? What kind of bags do you use?
Do you have a point-of-sale system now?
Be prepared. Work with your team and come up with at least 6 different questions you can ask to make a friend.