Saying the Law is X, but don't practice it [Halachah ve'At Lo Taaveid Uvda]: Ketuvot 14a
Saying the Law is X, but one should not teach it [Halachah ve'Ein Morin Ken]: Eruvin 6b-7a
Teaching that X is Halachah, and then adding that X is practical Halachah [Halachah l'Maaseh]: Ketuvot 56a
Not teaching a potential leniency, if the questioner isn't a "Person of Torah" and may mistakenly extend the leniency: Shabbat 139a-b, 153b; Nedarim 23b
Whispering a leniency, lest it lead to an inappropriate practice: Berachot 22a
Not following a certain rabbi's opinion, because it might give his opinions general credibility: Niddah 7b
For a Rabbi to rule leniently for the community, but stringently for himself: Shabbat 134a; Bava Metzia 74b
A Rabbi may not say, "If the circumstances of my examination were such, I would have said..."; the judge only bases on what he sees: Niddah 20b
Use, or non-Use, of the Term "Horaah" in Reference to a Stringency: Ketuvot 7a
[Lack of] Use of the phrase "Darash," indicating that an enactment is verse-based: Succah 41b
Use of the term "He enacted" vs. "He analyzed [a verse] and established": Rosh HaShanah 30b
The establishment of thresholds of consumption, or other acts, for different mitzvot/transgressions is exact: Rosh HaShanah 13a
Specifically those who hear a ruling must follow it: Kiddushin 13a
Voting in a Group ["Nimnu veGamru"]: Ketuvot 63b; Makkot 21b; Temurah 7a
Not repealing a verdict, once it has already been issued: Gittin 6b
Differentiating between law and popular practice: Eruvin 62b [and see Rashi s.v. "Halachah" and "Minhag"], 72a; Taanit 26b
Not issuing a legal ruling which has no relevance until Mashiach arrives [Hilchita l'Meshicha]: Zevachim 44b-45a
