Kim was a kid being trained by the British to be a spy against the Russians in Rudyard Kipling’s 1901 novel of the same name. Kipling, while living in Punjab(now Pakistan) wrote for a Military Gazette and thus wrote about things he observed in the genesis of his career.
Kim’s Game is the definitive skill-builder for all things observation. The trainer lays out several items. The observer looks over and handles them.
Look on them as long as thou wilt, stranger. Count and, if need be, handle. One look is enough for me. When thou hast counted and handled and art sure that thou canst remember them all, I cover them with this paper, and thou must tell over the tally to Lurgan Sahib. I will write mine.
[Do] it many times over till it is done perfectly – for it is worth doing.
This is the simplest, best method I know of for building memory and observation skills. Your brain is a muscle too- it develops memory and routine just like every other part of your body. Find ways to implement this into your training program.