Best practices to call model methods in java servlet

I am working in a java web base application. I have created a package for my model classes. Right now, I am calling the methods of these model classes from the servlet, but I wanted to make separate classes for each of my model class in which I can write my business logic, because by doing this my code will be more manageable. I do not know what are the best practices for this, and secondly I know there is a mvc software architectural pattern. I am wondering that is there any design pattern which I can follow for my application ?