I'm also really interested in this subject. Thanks for all the tips!
A few months ago I posted an article on by blog with ways to increase your mind power:
15 Ways to Increase Your Mind Power | Everyday Improvement
Some of the ways include:
- Neurobics
- Mental math tricks
- Mind mapping
There's also a book by Steven Gillman, called 100 Ways to Increase Your Mind Power. The link is somewhere in the article, I think. Not everything is that useful, but it gives you enough to work on.