Much depends on the kind of criminal law class you're taking. Criminal law is one of those subjects where professor's takes on the class can vary dramatically from school to school. Usually, we recommend that you learn the backbone of the subject itself from some outside source as a starting point, so that you can make sense of what your prof is doing in class. In general, we do not recommend using hornbooks-- they are mostly like encyclopedias of law. They can be a good place to look something up, but it's unlikely that they'll clear up any confusion. As for E&E or Emmanuels, some students do like these supplements, but we'd urge that you actually read one before buying. If it's not helpful to you, don't buy it just because classmates have it. Ideally, you need to create a "running outline" by combining outside sources, classnotes, classroom experience and homework briefs. For more info on how to do that, give us a call!
Brainstorm about the "Erie Doctrine" so that you can spot the Erie question on exams. The Erie question will come up only when parties are in Federal court based on diversity jurisdiction (if you're not sure why, take a minute and think about it). Your fact pattern will need to contain some kind of state statute. Often, there will be a federal statute that potentially conflicts with the given state statute but sneaky law professors don't tell you about the federal statute. Instead, they give you a state statute that is very similar to a FRCP and its up to you to realize that the FRCP is the Federal rule that is used in the Hanna analysis.
Proximate Cause freaks everyone out. Learn it in a way that actually works. Most people understand proximate cause best when they think about things that fail the proximate cause test because they are not foreseeable. When someone is careless, most of the time, the resulting damage will be considered foreseeable. In order to be considered unforeseeable because it's blamed on a superseding event, you'd need to see an act of God or Nature, A criminal act or intentional tort of a third party, or an act by the victim himself.
Res Ipsa Loquitor is not the name of a tort. Res Ipsa is simply a method of proving duty and breach. Professors will often tell you that Res Ipsa is a "shortcut" and that's true it IS a short cut at TRIAL. Res Ipsa is not a shortcut on an exam. In fact, Res Ipsa requires you to discuss an entire three-part test.
Think about why you learned the Learned Hand Formula. Everyone knows that in a negligence case, we say that defendants have the duty to act "reasonably". The Hand formula is one way to solidify what "reasonable" behavior might mean in a particular situation. This is not the only way to define "reasonable" it's just one way. Other ways include using common sense, looking to industry custom, or consulting a statute.