Of the many methods and means for learning, to begin it is essential for one to learn to think for oneself, without simply repeating what others have said. Making one own's decisions rationally and with sincerity comes only from thinking things out. Looking at both sides of the picture, to determine what is wrong or right...for you!
Consider that what might be correct for someone else, might not be so for you. So give deep thought prior to making decisions so that you do not end up regretting the one you made.
Read. Find out what the great minds have thought about things. This means the classics, which are easily found in book stores or libraries. Classic novels are a much more entertaining way of learning how others think than dry text books, on anything from ethics to philosophy. Classics are usually more than just about the upper classes (which many of them are). Rather, they should discuss ideas that concern that which is considered as universal to the human condition.
Consider agnosticism. An agnostic neither believe nor disbelieves. To believe one thing is to exclude all other opinions to include one's own. The problem with this mindset is that it excludes opposing ideas and opinions.
If one suffers from mandated faith, then one can no longer share in another's opinions. To believe nothing, means anything from one's own existence—from the Big Bang, to Evolution, to the latest theories on what to eat—should be subject to questioning. This means that every statement is a question. "I believe there is no such as free will" is end of discussion. However if the subject is open, there is room for much if not endless speculation, since the universe is an open system. Question that statement.
Ask questions. To be interested in learning how to think one should be inquisitive. Ask questions and try to answer to them. It is only by asking questions that one creates context, for which to take interest and notice things that may relate. It is only by attempting to answer questions simply and clearly, that one can measure his or her own understanding of things. Understanding is the gateway to compassion and doing away with vices such as confusion, false ideas and misplaced blame.
Propose alternative theories to today's accepted ideas and understandings. The correctness or rightness doesn't matter, so much as the creation of new ideas, speculation, theories and concepts. What is important is the testing for validity. Every new idea as theory or concept should be tentative, subject to testing for its validity. If nothing is created, then there is nothing to test. Theories can be correct when self-contained by their own internal logic. One can believe anything they want, so long as it is not contradicted by one's own sense of wrong. However, most original thinking in the interest of truth should be tested by discussion, observation, argument, and personal experience. Bad ideas can lead to good ones, as they can take one in a direction one might not otherwise have gone. Untested ideas can be sheltered until they are strong enough to stand the test.
Simplify, reduce, and categorize. Ideas can come a mile a minute at a rate in which the mind cannot know what to do with them. One can write them down but then they tend to get lost in a maze of paper and writing may not be fast enough or convenient. One might create categories in the mind as repositories for ideas as associations. Categories can be questions one is working on, general subjects like history, theory of relativity, ancient man, red light shift, concept of how, love and hate, or ego. Associate ideas from books and movies to present circumstance and vice versa. Simplify the mish-mash within the categories, by attempting to reduce the many ideas to commonalities, for instance as Marx did reduce many if most of the many motives of mankind to economics. You should not drive yourself nuts with intellectual constancy. Rather ask questions make statements, make observations write them down or categorize and forget about them. Free association is healthier for the mind. The idea is come back to the problems one has set for oneself and to remember to come back circular fashion, freeing the mind to free association, day dream or whatever. The mind works on problems subconsciously. Come back and see what new may be there.
Analyze your surroundings. This is another means to help you think for yourself. This essentially means examining why someone thinks and believes that which they do, the origin of that thinking, and the possibility of motives that may or may not lie behind them. This involves taking common assumptions that you may have heard or been taught, and questioning it. This might be common knowledge or even actual experience.
Examine it. Ask yourself, "Why is that true? Why do I believe that? Is it valid if I have not proved it myself?"
Immerse yourself in artistic/creative outlets. Write a song or poem. Draw a picture. Build or cook something from scratch. Valuing your own creativity is a key step on the road to independent thought.
Avoid one sided systems such as political parties or organized religion. Any of these things will work toward closing your mind, rather than opening it. You should be able to adapt yourself to any perspective—not limit yourself to a single one. Belonging to a group invokes in most people of average intelligence—a "group mentality".
If you don't agree with a particular "law", or "rule", then DO NOT FOLLOW IT! The consequences are probably worth the peace of mind that you get knowing that you stood up for yourself. Keep in mind that YOU only get ONE life. If you spend your life following orders, you'll follow them right to your grave.
As one learns to think independently, one may change one's values and become intellectually and emotionally at variance with one's family, friends and community.
Being too independent may cause one to be labeled as "socially maladjusted" or "crazy."