First, pay attention to the conditions that the basic theorem should meet. Basic inequality can transform sum into product and product into sum, but we must pay attention to the preconditions of application: "one positive", "two definite" and "three phases". The so-called "one positive" refers to the application theorem.

Second, we should pay attention to the consistency of the conditions for the establishment of basic inequalities. In view of this situation, we should remember that the conditions for the establishment of the equal sign should be consistent in the continuous use of this theorem. For some problems, it is not suitable to find the maximum value directly with basic inequalities, but we can use basic inequalities by adding terms, separating constants and squaring.