Scientists studying how sleep affects memory have found that the whiff of a familiar scent can help a slumbering brain better remember things that it learned the evening before. A rose bouquet — delivered to people’s nostrils as they studied and, later, as they slept — improved their performance on a memory test by almost 15 percent.Researchers suggest that acrid smells may be even better at enhancing memory, although they may be less pleasant to endure if you're looking for something to help you cram for an exam. But that begs the question: do you have any tips or tricks that aid memory retention? It's been a while since I had to memorize anything, but back in university I found that typing notes rather than writing them out helped my retention considerably, perhaps because I was spending more time paying attention to what I was writing rather than the mechanics of writing itself. What works for you?