repetition is the first method by which you can remember any information for a long period of time. next is to imagine what you are reading. example: if you are reading about the growth of a plant, imagine it in the similar way with the labels. it will stay in your mind for a longer time. look and read aloud, this will imprint the information in your mind.
My father had an excellent memory right up until the day he died in Hospice care at an old age. He worked crossword puzzles and played the card game of Bridge for years. I think that contributed to his sharp mind.