How to increase brain's overall performance?

Use it or lose it: There are three principles of how brain cells, or neurons, work: 1) What gets fired gets wired. When you practice thinking or doing something, neurons in your brain make connections, or synapses. 2) Use it or lose it. If these connections are used consistently, that is, you practice something again and again, they get strengthened. If you do not use them these synapses will weaken and disappear.