Method's eight rules in La Logique ou L'Art de Penser

This rules derive from Pascal, Descartes, the Scholastics, and possibly Ramus. Here they are:

Two rules concerning definitions 

1. Leave no term even slightly obscure or equivocal without defining it.
2. In definitions use only terms that are perfectly known or have already been explained.

Two rules for axioms 

3. In axioms require everything to be perfectly evident.
4. Accept as evident what need only a little attention to be recognized as true.

Two rules for demonstrations

5. Prove all propositions that are even slightly obscure, using in their proofs only definitions that have preceded, axioms that have been granted, or propositions that have already been demonstrated.
6. Never exploit the equivocation in terms by failing to substitute mentally the definitions that restrict and explain them.

Two rules for method 

7. Treat things as much as possible in their natural order, beginning with the most general and the simplest, and explaining everything belonging to the nature of the genus before proceeding to particular species.
8. Divide each genus as much as possible into all its species, each whole into all its parts, and each difficulty into all its cases.

References
In Arnauld and Nicole, Logic or the Art of Thinking, Cambridge, p. 259.
Jong, W.R. de, Betti, A. () The Classical Model of Science: a Millennia-Old Model of Scientific Rationality. Synthese, 174(2), 185-203