A big part of it has to do with levels of brain-derived neurotrophic factor (BDNF), which helps keep neurons healthy and aids in the formation of new synapses and neurons so it is obviously directly tied to being able to form new memories)memories. Some ways I know how to boost it: exercise, meditation, sleep, pantethine*, DHA, blueberries (and probably other berries) and I'm going to hazard that just generally good micronutrient status supports this.
Protecting the brain is important, much of what I just mentioned and nutrition in general protects the brain. Of course we want to do all of the normal good paleo things to reduce inflammation, oxidative stress, and anything that damages the brain. So make sure glutathione is supported by getting enough sulfur and sulfur-containing amino acids, and utilize anything that will protect the brain from damage. I like astaxanthin as a powerful protector**. Other things that damage the brain are excitotoxins, toxin toxins, and too much of various minerals like iron, manganese, copper, zinc, lead, mercury. It is actually good to get your iron levels checked and make sure they're not too high, but be sure to test first.
So in general I think that a paleo diet and lifestyle is ideal, and that there is merit to taking various supplements to get a boost. Check out Evolutionary Psychiatry if you haven't already http://evolutionarypsychiatry.blogspot.com/ and just try to take care of your brain as best you can. There's more to it than what I mentioned but in general the health of what tends to keep the brain healthy is taken care of but the things that keep what keeps the rest of us healthy.
- http://www.wellnessresources.com/tips/articles/pantethine_boost_your_brain_cardio_health_metabolism_and_detoxification/ This is as close to a hack as I get, I'm more of a slow-and-steady type of person.