Keep track of potential “gifts” and make a wish list for them. All it takes is listening, and adding it to a running list in your phone.
When they share about something they’d love to have or something that would make life easier or better, add it to the wish list. (For super techy people, you can even put it on a ‘product tracking site’ so you are alerted when it goes on sale.) Then, when it’s present shopping time, or even when you just want to get them something, pull out the list that they essentially created without knowing it.
They’ll be so touched that you remembered what they had said. And thrilled with the gift.