I might use checklists for both of these things. For the dish/restaurant example, I have a checklist called "Next Time In..." and I have various things listed by cities I sometimes go to.
For the gift item, I have a list called "Gift ideas" and I'd just make a general note there. I listen rabidly to friends and family for ideas for gifts for them, and keep track of it all there, by name. I get lots of kudos from people that are "amazed" that I seem to always know the perfect thing to buy for them. Of course, they have no recollection of ever having mentioned a thing to me!
I am the Party