There are two ways to develop the brain: learn to think independently or accumulate other people's knowledge. Both directions, of course, are important, but it is the latter that is commonly called the "broad horizons" and "high education."
Instruction manual
one
Develop memory. There is a lot of educational literature that will provide you with a ton of options on how to do this. The simplest ways that we are accustomed from childhood to learn poetry and prepare for tests. Of course, the education system is imperfect, and there is no desire to memorize something “from under the stick”. However, pay attention to the fact that the mere desire to study can several times improve the results of the student. The fact is that there should be a desire to work on yourself.
2
Read classic or globally recognized literature. During reading, a huge number of processes occur in the head that develop intelligence only because they occur. At the first stage, the brain tries to recognize obscure characters and concatenate words from them (at the same time, it determines only 50% of the word, and thinks out the rest itself). Further, a similar process occurs during the compilation of words in a sentence; at the same time you draw a picture in your imagination and analyze, think about what you read. And if you read poetry, then a dozen more nuances associated with rhythm are added to this.
3
Watch a movie, study painting, play computer games. In other words, study everything that may have at least the slightest relation to art. If you have any doubts about the last point, here is another great tip for developing your mind: stop thinking with stereotypes. Introduce yourself to games like Braid and Bioshock. In fact, in the gaming industry there are many projects that are an example of impeccable taste and can deliver a lot of aesthetic pleasure. As in the "stupid Japanese cartoons" - anime.
4
Accustom yourself to write essays on what you have read and seen. At the time of writing, you will not only put a strain on the brain, but also begin to think more carefully about the work, find subtexts and thoughts that the author tried to convey. Moreover, when you fully penetrate and understand the meaning of the book, you are unlikely to forget it in the next couple of years and you can always show off erudition in front of friends.
note
Be sure to enter a quote book, a list of read, a list of viewed.
Useful advice
Use ratings and chats. For example, you should start watching movies with IMDB top-250.