In the free Coursera course "Learning How to Learn" by Barbara Oakley, there are many useful techniques and inspiring interviews. EVERYONE, no matter your discipline or stage in your career, is highly encouraged to check it out.

One key idea from the course is that we need to understand the focused and diffusive modes of the brain and use them on suitable occasions, to help short-term and long-term memories to form, to build the chunk library, and to allow the brain to do its work in creative problem-solving.

This range of gamma brainwaves is associated with strong feelings of happiness and compassion, high level of learning, and problem-solving.

This is often when people are in the focused mode. It takes high energy, and the Pomodoro Technique (work intently without disturbance for 25 minutes and then take a 5-minute break) works well to make it efficient and rewarding.

This range of beta brainwaves is the normal waking or thinking mode.

The conscious mind is often not the most effective or creative, though. We often need to make a conscious choice to activate the visual/spatial part of our brain, such as using Memory Palace (to place provocative imagery or visualization associated with something we want to remember in a familiar environment such as our home) or placing the association of someone's name to a prominent feature of that person's face to help us remember their name (so that we'd remember the name when we see the face, instead of having to search elsewhere in our brain).

This range of alpha brainwaves is when people are relaxed. Many hypnotists working with eradicating habits are using this stage of light trance. Alpha brainwaves happen more often than we think. When we watch TV, we often fall into this alpha brainwave within 60 seconds, and the TV commercials are made to be suggestive. However, this is also the stage when people are very creative, or the brain is in diffused mode.

When we try to solve a problem and nothing seems to work after many attempts (or after the brain has been in the beta or even gamma brainwaves), it is a good time to step back, such as exercising, listening to music, taking a walk, or taking a bath, to allow the brain to enter the alpha brainwave, and the brain will do its own work to connect the dots and often find the solution quickly.

The switching of the brainwaves is essential. The problem has to be worked into the brain as a family member through beta or gamma brainwaves, and then the brain can work with it with alpha brainwaves. The interleaving of multiple modes is critical. For example, the "Hard Start - Jump to Easy" approach during test-taking is to start on a hard-looking problem, even if you may get stuck, but jump to easier problems after you spend a few minutes with the hard-looking problem, so that you can let your diffused mode of the brain to start working on the hard-looking problem. Then when you finish a few easy problems to go back to the hard-looking problem, you may discover that you've already known a few more steps, even if you still don't have the final answer yet. Then you go to work on more easy problems. This approach could be applied multiple times during the test. Simply working on the easy problems first won't start your brain to work on the hard-looking problems and you may feel pressured when you have limited time to finish the hard-looking problems in the end.

Another great piece of advice on writing is based on the switching of the creative and critique modes of the brain as well: Do NOT edit while writing. When we are writing, our brain is in the creative and diffuse mode, so, let all the words come out, and keep the momentum of the ideas going. Do not edit while writing, as the editing is to put the brain back to logical reasoning and focused mode, which often blocks the flow of the ideas, and gets us stuck. Oftentimes, the sentences that we thought were bad when we were writing were not too bad when we read them within the context during editing after all.

This range of theta brainwaves is when people enter a deeper level of relaxation or deeper trance, right before they fall asleep or right before they wake up. It is a natural phase that people go through every day. Experienced mediators or some hypnotists can prolong this stage, and this stage is considered to be connected to the group consciousness to have much wisdom and healing.

The diffused mode of the brain may also access these theta brainwaves, besides the alpha brainwaves.

This range of delta brainwaves is when people are asleep.

Sleep is essential for humans and animals, as during sleep, the toxins generated during the active period, surrounding the neurons, could be washed away when the neurons are shrunk in size during sleep. Sleep time is also when long-term memories are solidified and filed into the brain. There are also many other health benefits due to sleep that we may or may not have discovered.

Many people may "sleep over" a problem and get an answer. The boundaries between the alpha, theta, and delta brainwaves, in terms of creative problem-solving, may not be so clear-cut.