A rule is when the law gives a specific value, like "$100". A standard is when the law says something like "fair market value".
Normative vs. Positive
Normative statements are "should" statements: "we should do X". Positive statements are "is" statements.
You cannot arrive at a normative conclusion given purely positive premises. That's known as Hume's law.
Ex Ante vs. Ex Post
Ex Ante is when you reason about what the law should be based on the effects of the law in the future. Ex Post is when you reason about what the law should be about an action that has already taken place.
Juries tend to reason ex ante, whereas judges tend to reason ex post.
People reasoning ex ante will tend to be more compassionate.
The Two-by-Two Box
Keep your eye out for situations in which three ways of doing things are listed, where the three ways are constructed from two binary distinctions. In those situations you may be able to construct a two-by-two box that reveals a less-frequently-used fourth way of doing things.
Example of the weird fourth way: A judge ruled that an old folks' community that had been built next to a ranch could force the rancher to move avoid having the community overrun with bad smells, provided that they compensated the rancher.
Default vs. Mandatory Rules
A law can either be a default rule or a mandatory rule.
If it's a default rule, it should be accompanied by "Altering rules" that dictate the necessary and sufficient conditions for altering the rule.
Every area of law is a mixture of default and mandatory rules.
Whenever you learn a new legal rule, ask whether it can be contracted around, and if so, how.
When setting defaults, the law tends to aim to set the default to what the parties would have hypothetically have contracted for, if they had expressly contracted.
The law will sometimes use "penalty defaults", which are designed to incentivize one or both parties to reveal information.