How does the brain physically get tired?
The first rule of Neuroscience Club is to check your Kandel.

The second rule of Neuroscience Club is to check your Kandel.

Joking aside, the gold standard of neuroscience is Kandel et al.'s Principles of Neural Science, currently in its fifth edition. It's an extremely (and in the cognitive sciences, I would say uniquely) comprehensive and authoritative work, and you can certainly use it to find an explanation for your questions about how the brain stores and uses energy, or virtually anything else. It's that rare kind of book which successfully distills a massive subject down to something as simple as possible, and no simpler than that.


  Kandel, E. R., Schwartz, J. H., &amp; Jessell, T. M., Siegelbaum, S. A., Hudspeth, A. J. (Eds.). (2013). Principles of neural science (Vol. 5). New York: McGraw-Hill.


It does not really make sense to talk about "how to use the brain as an organ most effectively." The brain is only metaphorically similar to muscles, and only in certain respects. One of the relevant differences is that neurons do many things and often exhibit nonlinear behavior, whereas muscles more or less only stretch and contract. This currently makes it very difficult to scientifically define what optimizing brain function means, exactly, compared to defining what optimizing muscle function means. 

I will not deconstruct the question further since it is primarily a reference request, and this will all be more than clear from Principles of Neural Science.