How do I figure out what a customer actually needs?

You can engage almost anyone now, which means the basics are behind you. What trips you is deeper: reading past what a customer says to what they actually need. That is a subtler skill, and wanting it means you are aiming at real service, not just a sale. What people ask for and what they need are often different, and the gap is closed by curiosity, not cleverness. Ask one more question than feels necessary. What are you trying to do with this tells you more than any guess. Then listen for the problem behind the request. Most people will show you their real need if you slow down enough to let them. One step: with your next customer, before you recommend anything, ask what they are hoping it will do for them, and actually wait for the answer. You will be surprised how often the honest need is one step to the side of what they first asked for. That step is where you become truly useful.