"стремиться делать изменение" is grammatical but meaningless. Do you strive for the process of changing of for a completed action? If the later, you should write "стремиться сделать изменение" but the word изменение in Russian if used in singular means "the change" (i.e. one particular change). If you mean just changes in general, you should use plural, thus "стремиться сделать изменения". This is more meaningful.