How to read a semantics

Some tips for myself on how to read a semantics:

1. Follow the textual description first. Usually they have thought about an order in which you should try to understand the rules.
2. If you get stuck on one of the rules, circle the part that's confusing or write down what you don't get and skip it. Don't spend too long on any one part. (More often than not I embarrass myself by beating my head over something confusing only to find that it's explained in the next paragraph.)
   
3. To understand the role a particular expression form plays, read its introduction and elimination rules. To understand the role an environment plays, read its extension and lookup rules. To understand any one of these rules, read its dual rule. Most of these rules make much more sense in pairs.

Another couple of general tips: take notes on the semantics and actually copy down the rules, but don't copy down the rules that are simple structural inductions or unchanged from previous variations. Also, take breaks. And never get caught reading papers after 2am.