The New Scientist has a lengthy article about sleep, and two germain things they advised for memorising were:

1) don't loose sleep to "cram" all night, for exams/interviews etc.

2) by reading/consuming info before sleep. Say in the evening.

Another leg on the stool.
One current understanding of sleep's purpose** is that of sorting the previous day's transactions and preparing the coming day's tasks. Tidying-up if you will.

**(in this context. Yea, yea, there are also physiological things going on in the brain like flushing out prions). We all sleep, some better than others!