There is no one way of critical thinking that is best. Critical thinking is about your mindset as you examine something, not about one technique that you can use. As the above response notes, there are many situations in which comparing and contrasting does not make sense as an approach. If you are reading an article or an essay, and you are expected to respond to it with critical thinking, you may not use a compare and contrast strategy at all. You will have an inquiring mind, questioning what the writer says, his or her sources of information, his or her logic, and so on. Comparing and contrasting is a good strategy sometimes when you have to make a decision about something, for example, whether to rent or buy a home, what college to attend, which car to buy. The reason students are often assigned to write compare and contrast essays is because this can be a good strategy to apply in one's life, and it forces one to break down two "things" into their elements in an organized way. But part of your critical thinking should be about not blindly applying just one strategy to everything you need to think about.