A few years ago I realized the most important part of gift giving is to devote some amount of time to really focus on a person and think about what they might want or like or need. In my opinion, this is the only part that matters, and if you take the pressure off of yourself for actually giving a great gift, sometimes you end up getting them something great anyway, because you're freed up to really meditate on them as a person.

Another tip is to pay attention to what kinds of gifts they give. Many times people just buy others things they want for themselves. e.g. my sister-in-law always bought women earrings, started getting her earrings to great effect!