I retain particular things in my memory. They usually have to have something I note as a quirk of some sort to be keepable, so if I want to keep a piece of information I might forget I have to attach something strange to the memory. In statistics, we went over Chebyshev's theorem and Empirical rule that both state percentages of data that fall into particular categories of deviation from the mean (of the data values) dependant on the distribution and I retained most of it by calling the theorem the "Chevy Chase theorem". Stupid, but now I'll remember it more or less forever. Or to give you another one, we have a type of plant in our front yard and I always forget the name. They're lantanas so I started calling them "Carlos Lantanas" and now I always rememeber.
But I get old ppl's memory a bunch. I'll go to my room for a pen and do twelve other things in ten minutes and then get distracted and forget completely. So I have to go back to what I was doing until I go to write something and realize I still need the pen I was suppose to get from my room.