The first condition to understand a subject quickly is to prepare itself of effective way for the class. Here I give you you rule methodological that you must follow to obtain this. to 1.Leer the main title of your subject and preguntarte that you know of. It is important to prepare a series of questions on the title that is? , as it happens? when? where? so that? It tries to respond them mentally, because to analyze and to include/understand the relations between the things we resorted to the knowledge available in our mind. It resorts to your experience and the information that you have on that subject. You can write down briefly that you know of the subject. In the end the important thing is that it awakes the curiosity and the interrogative ones to you on the subject.
But we apply all this on a concrete example: Subject: It limits of Functions. Podrias preguntarte with respect to this subject: That it is limits of a function? as they are the classes of you limit of a function? Where it is applied limits of functions? to that it must the name of limits? Once you become these questions, already you condition your mind to respond them. All these questions wraths solving more clearly as the subject is developed. Obvious if you know to some answers slogans in your notebook of notes. 2. To read the introduction and the conclusions of the subject. In these sections of brief and concise form one is transformed the main content and the most important aspects of the subject. This contributes to distinguish, during the reading, the interest of the different contents from the lesson. We follow with the same example of limits of functions: You are going it generally to the introduction to find at the beginning of the subject and the conclusion at the end of the subject.