In general, human memories are processed in three steps.
Encoding - Which includes the input of the information
Storage - this process refers to the saving of the information in our memory space
Retrieval - The process of searching a certain memory in our memory space and taking it out.
The most efficient method for improving memory would be by utilizing your right brain plus all of other senses during the Encoding + Storage process.
Make the information unique and interesting.
For example, if you want to memorize a certain number, try transforming the number into characters/visual image (0 - wheel, 1 - snake, 2-Duck, etc. .)