The technique of scanning your application for common elements applies as much from a code perspective as it does from a visual perspective.

While writing instance methods that enhance your visual parts, look for common scripts or script segments. These common scripts are perfect opportunities for reuse and can possibly be placed in an abstract class.

Abstract classes are Smalltalk classes that factor out common behavior. Abstract classes are not intended to define any particular real part, but rather, are a repository for common instance methods. The similarities between your various parts will determine which parts should go into a common abstract class.

Using abstract classes gives you all the benefits of reuse, namely increased productivity and reduced maintenance, because you only have to write and maintain the scripts in one place.