Fortunately, many have been written. In addition to conventional stuff like memory training, vocabulary building, etc. I highly recommend exploring (self-)hypnosis.
To your question: your mind is much larger, if you will, than the part you're conscious of moment to moment. You can learn to let it do thinking for you. (In fact, you have: language, walking, etc. your mind learns and operates vastly complex systems. That's why the brain is so large. It uses something like 20% of the oxygen you take in.)
Subjectively, you cram your brain with information (mostly via reading and direct experience. Take a train trip, etc. Get out and gather primary data.) Then sleep on it, often literally. Next thing you know, in the shower, or while buttering your toast, out of the inky blue will come some great insight, or a solution to some problem. (Be sure to keep a pad of paper and pencil handy at all times, esp. by your bedside.)
HTH, ta!