The DR number, Diederich Rank, refers to the highest number in Diederich's frequency listing, which you can see here: Diederich Ranking.
DR 189. Doctum doces. ~ Note: This is one of the sayings that Erasmus included in his Adagia, 1.2.12. It is a fool's errand, of course - the one who has already learned does not need you to teach him.
DR 189. Ire docetur eundo. ~ Note: The impersonal passive here, docetur, can be rendered with "you" or "one" in English: You learn to walk by walking.
DR 190. Maiores sequor. ~ Note: The masculine plural, maiores, refers to the "very great people" or "the ancestors" ... or "the mayors" if you prefer (our English word "mayor" derives from the Latin "maior").
DR 190. Maiora sequor. ~ Note: Here you have the neuter plural, not the masculine plural: I pursue greater things.
DR 190. Ad maiora veniamus. ~ Note: Note the subjunctive, veniamus: Let us move on to greater things. The idea is that we are setting aside trifles in order to move on: Sed nimis multa de nugis: ad maiora veniamus. You can find these words in one of Cicero's Philippics, 2.
DR 190. Totum parte maius est. ~ Note: You can find this expression in Euclid's Elements.
DR 191. Ne magna loquaris. ~ Note: The use of "ne" plus the subjunctive is a common way to express a negative command in Latin, as here: ne loquaris. (The indicative second person would be loqueris; just change the vowel and you've got the subjunctive: loquāris.)
DR 191. Res ipsa loquitur. ~ Note: You can read more about this legal principle in Wikipedia.
DR 191. Qui de terra est, de terra loquitur. ~ Note: You can find these words in the Gospel of John, 3, and the saying is included by Polydorus in his Adagia, B32.
DR 193. Vox populi, vox Dei. ~ Note: This Latin saying survives in the terminology of modern broadcast journalism, where "vox pop" refers to the voice of the man on the street, when reporters randomly ask people for their comments. The saying is first cited by the medieval English scholar Alcuin; compare also the similar saying, "Haud semper errat fama," "Rumor is not always wrong." The saying is included by Polydorus in his Adagia, B225.