Quintilian, and J.S. Watson. Institutes of Oratory. Edited by Lee Honeycutt, 2010. Kindle Electronic Edition. Book 10 Chapter 5.
In book 10 chapter 5 Quintilian considers what kind of writing is most valuable. “What is now to be considered is from where copiousness and facility of expression may be derived” (Quintilian X.5.1). He advocates translation of Greek works into Latin. The Greeks provided excellent examples of depth and breadth of invention. Their language difference provides considerable room for exercises of thought (Quintilian X.5.3). He also advocates rephrasing and retelling works already in Latin (Quintilian X.5.4). This practice makes the student observe a work carefully and practice care with wording (Quintilian X.5.8). Original writing about a variety of topics is also of great benefit (Quintilian X.5.10).
Compositions should include theses, refutations, and defenses (Quintilian X.5.11-12). Commonplace writing is also useful. Speaking of familiar questions in an intelligent and fluent manner is helpful to the orator. Quintilian also advocates writing of declamations, especially adapted to real cases (Quintilian X.5.14). Experience with real cases is of great value (Quintilian X.5.20). Working with current information grounds a student in the reality of conflicts. The teacher should also work to correct and improve writing (Quintilian X.5.22). This is of great value to a budding orator.