From No Limit Hold 'em: Theory and Practice by David Sklansky and Ed Miller.
Concept No. 59: Don't help your opponents play correctly.
I agree with this one, and it seems incontrovertible, but there is at least one example of advice that suggests you should help your opponents to play correctly. I think it is worth considering.
Barry Greenstein has a total of eight "play lessons" in his book Ace on the River. Lesson 5 says the following: "If your bets define the strength of your hand, it may make decisions easier for you on later streets." The idea is that if you confuse your opponents too much, you will have trouble interpreting their plays later in the hand, and you won't know how to react. I think Dan Harrington may have similar advice in his book, but I can't quite remember. Anyway, I think Sklansky and Miller's concept holds up despite Greenstein's lesson. You can use Greenstein's advice for your made hands but still make it difficult for your opponents to play correctly if you play bluffs in the same way. However, bluffing actually seems to go against Greenstein's Lesson 5. He suggests you let "your bets define the strength of your hand." This implies that you should not let your bets "equivocate" (my word, not his), which is what happens if your bets could mean either a bluff or a made hand. Bluffing occasionally seems to go against Greenstein's Lesson 5, and so it should not be taken too seriously. I have to take Team Sklansky's side on this one.
Okay, just one more concept to go. Hopefully, I'll finish this year after all!