Every time you think of a good gift for someone, write it down on your gift list. It can be a piece of paper in a drawer, or a part of your contact management system online.
Listen to your friends and family. They might mention something they need. Maybe they talk about something they used to do and enjoy.
When the time comes to give a gift, you can go back to your list and have plenty of ideas. Plus, they'll be touched that you payed close attention to their needs.