How to improve brain power is very much akin to how to improve muscle power.
If I want more strength in my bicep, I need to increase the number of muscle fibers in my bicep, by using resistance training.
When I stress the muscle doing curls, my body will allocate muscle building resources to the bicep, increase the number of muscle fibers there, and viola, my bicep grows.
The same techniques work for brain power, although the human brain actually aids and abets the process by creating new brain cells everyday for us in a process called neurogenesis.
The resistance training is providing our brains what is called a novel learning experience. If those new neurons are not challenged by some basic change in our routine, perhaps like using the other hand to work your computer mouse, (did you shudder?) or a computerized brain fitness program, your brain may not keep them.
When challenged those new brain cells migrate to the area around the hippocampus where memories are made.
Without our memories folks, we lose who we are, and that is a sad thing to have happen.
OK, so we can do some resistance training to lock in the day's new neurons, which enhances another very important aspect of the human brain, its neuroplasticity.
Neuroplasticity is the word used to describe the brains constant efforts to rewire itself by neurons searching out new neurons for connection. If those connections are deemed beneficial by your brain, a process which happens in your sleep, they are kept and are available for improved brain power.
The more neurons available for connections, just like muscle fibers in the bicep, the more mental hefting you can do, and the longer you will keep your memories.
If you are not going to try out using your less dominant hand to run your computer, then you might want to try out the Mind Sparke Dual N Back task as a way to challenge your brain, or the Become Second to None program. Either program can be easily included in our daily schedule, like a trip to the gym. The research on the tools was made public in 2008, so it is very new, and interestingly enough, one of the results of the practice is an increased IQ.
You can find links in the right sidebar. AT 64 years of age, I am practicing my how-to-improve-your-brain workouts regularly.