There is no fixed treatment method for this, which varies from topic to topic. But I can give you some advice, I hope it will help you.

The denominator is higher than the fraction of the molecule, and the first thing that comes to mind is the separation constant (formula) method, which is to find ways to make the molecule appear in the form of denominator, thus reducing the order and transforming it into an inverse proportional function.

Fraction with denominator lower than numerator. Generally, we should first think about whether we can use the basic inequality, that is, the denominator of the molecule can be divided by a formula at the same time, and most of them are formulas with the form of y=x+ 1/x on the denominator.