Those are all great suggestions. Personally I feel an enormous difference in mental function when I keep a regular practice of some kind. Be it Yoga, martial arts, meditation, even just bicycling around the lake every morning will do wonders for supercharging your brain. It's all about getting things flowing. Too many of us are sedentary, and our body's slow decline into rigidity is mirrored by our minds.

Try these herbs as well, for more mental agility.

Rhodiola Rosea
Bacopa
Gotu Kola
Turmeric

enjoy!