There are also a lot of good youtube channels on memory improvement/techniques, as well as online resources. I’ll bookmark this post and add a bunch when I’m at a desktop, using this forum from mobile isn’t as easy/smooth as it could be.°
*first edit: also, having a “perfect memory” is probably impossible, no matter how much one works on it, unfortunately One can have a “great” memory and be very very sharp even into old age. A big part of that will be connected to diet and exercise actually. One’s brain (and memory) is not going to fire on all cylinders with a diet consisting of twinkies and cheeseburgers.