This Newsweek article has a couple of familiar tips (physical exercise and meditation), but the third one may come as a surprise.
Finally, some videogames might improve general mental agility. Stern has trained older adults to play a complex computer-based action game called Space Fortress, which requires players to shoot missiles and destroy the fortress while protecting their spaceship against missiles and mines. “It requires motor control, visual search, working memory, long-term memory, and decision making,” he says. It also requires that elixir of neuroplasticity: attention, specifically the ability to control and switch attention among different tasks. “People get better on tests of memory, motor speed, visual-spatial skills, and tasks requiring cognitive flexibility,” says Stern. Kramer, too, finds that the strategy-heavy videogame Rise of Nations improves executive-control functions such as task switching, working memory, visual short-term memory, and reasoning in older adults.
Well, at least now we know that World of Warcraft, so popular among many chessers, actually does some real good!