The DR number, Diederich Rank, refers to the highest number in Diederich's frequency listing, which you can see here: Diederich Ranking.
DR 66. Unius dictum, dictum nullius. ~ Note: This Latin legal maxim expresses the principle that one witness is not enough; you need corroborating evidence. As a result, the word of just one person is no better than no word at all. This saying is also a great way to remember the genitive singular endings of unus and nullus; they both take that -ius ending.
DR 70. Erat manus Domini cum eis. ~ Note: The words are from the Biblical book of Acts, 11.
DR 71. Alii alio modo. ~ Note: This is one of those "aliud…aliud" sayings, allowing the Latin to be extremely succinct! We would have to say in English, "Some people do things one way; other people do things another way."
DR 71. Est modus in rebus. ~ Note: The word "modus" here expresses the idea of a limit or a measure, as in the English word "moderation." The idea is that there is a limit to things, a measure that is proper to each thing.
DR 71. Faciam meo modo. ~ Note: You could call this the Frank Sinatra proverb: "My Way" (the lyrics are by Paul Anka, though).
DR 74. Omnes terra sumus. ~ Note: Note that omnes (masculine plural) agrees with the implied subject of the verb: Omnes (nos) terra sumus.
DR 75. Unus vir non omnia videt. ~ Note: Notice the nice alliteration between vir and videt in the Latin; vir is preferred to homo here not for semantic reasons, but for the stylistic appeal of the alliteration.
DR 77. Omnis est rex in domo sua. ~ Note: Compare the English saying, "A man's home is his castle."
DR 81. Est gula totius fons et origo mali. ~ Note: Note how the genitive phrase, totius mali, wraps around its noun phrase, fons et origo.
DR 81. Non sibi sed toti. ~ Note: This saying is a great way to remember that totus is one of those adjectives (like solus, unus, ullus, etc.) with a genitive in -ius and a dative in -i.