First, let me echo that I don't think 1L prep is necessary for doing well in law school. Maybe it helps a little, if you do it right. Maybe it would be more helpful to drink a lot and just relax before school begins though. But since people want advice for how to prep, here's my advice on what to focus on.
0L prep:
1) Update and turn your resume into a legal resume (include your law school on it). (Google “Sample Legal Resumes” for examples—I just did that search and George Mason had a pretty helpful 28 page word document on how to make a legal resume.)
2) Start research firms in the areas you want to be working and take a crack at writing 1L SA cover letters for them. (You might want to use NALP and/or the firm’s website to see if they hire 1Ls.) Also, figure out how to do a mail merge if you don’t know how. For help on writing cover letters, see
http://www.law.berkeley.edu/1147.htm, or just google for more examples. For help on researching firms, see
http://www.nalpdirectory.com/,
http://www.chambersandpartners.com/USA, and
http://www.vault.com/wps/portal/usa/ran ... Range=1-25.
Also start looking up federal district judges and COA judges in the areas you want to work and take a crack and writing 1L judicial internship cover letters. Use google for samples. Use Wikipedia for lists of judges.
Do the same for public interest organizations too, if you’re interested. (I can’t be as specific for how you start doing this though, since I have no clue. Google will probably have answers for you though.)
3) Consider buying the following book for help on #1 and #2:
http://www.amazon.com/Guerrilla-Tactics ... our+dreams. The book can be a bit fluffy at times, as well as overly optimistic about how you can “create job opportunities” for yourself, but it can help acquaint you to how legal hiring works.
4) Read Getting to Maybe and Guides on TLS on how to succeed in law school. When you are reading the guides, keep two things in mind: 1) No method works best for everyone, and 2) the challenge of 1L year is trying to figure out what study methods work best for you. So how do you figure this out? By seeing a lot of different styles that worked for another people and trying to figure out what plays most to your strengths. Also, keep in mind that some methods may work better for some professors. So be flexible.
5) Buy and start skimming through the following two books:
http://www.amazon.com/Elements-Legal-St ... 0195141628 and
http://www.amazon.com/Academic-Legal-Wr ... al+writing. A good chunk of Volokh’s book won’t be applicable yet, but he’s got some great general info on legal writing. Working on becoming a strong legal writer is an important part of law school. (And if you were an English major, you might have to adjust to a style of writing that is much less fluffy and verbose.)
6) Make a folder of important documents: Include in it transcripts from all the schools you’ve attended (unofficial transcripts should be fine—just make sure you always have at least one copy of each), a current passport, and your social security card. Also consider gathering some of the stuff you’ll need for your bar application or your declaration to study law application: A list of all the employers you’ve worked for since 18 and the name and number of the supervisor you worked under (if the supervisor isn’t there anymore, then don’t worry about it), documentation of any sort of infraction you got during undergrad, documentation of any sort of legal troubles besides speeding tickets, etc. The longer you wait to gather some of this info, the harder it can be to get.
7) Consider working on your typing speed. I think typing speed can be overhyped in terms of how much of an advantage it can give you, but if you’re bored and got nothing better to do, there’s no harm in seeing how fast you currently type and how much you can improve by the time school starts.

If you really want to do some reading that involves law, focus on things that give history and back. I would recommend buying the following supplements and reading the following sections and chapters: § 1.04 [Studying Constitutional Cases] and Chapter Three [Incorporation] in Dressler, Understanding Criminal Procedure: Investigations (2010); Chapter One in Chemerinsky: Principles and Policies, 4th edition (2011); Chapters One through Four in Dressler, Understanding Criminal Procedure, 6th edition (2012). Chemerinsky and Dressler’s Crim Law supplement are staples no matter what law school you go to or what professor teaches you either of these classes. The Crim Pro supplement provides a great, quick breakdown on how to read con law cases and a really good and concise summary of incorporation—an important topic you’ll cover in con law. Both are done with a slight crim focus, since it is a crim pro supplement, but it’s completely applicable to con law and if you take crim pro: investigations as a 2L or 3L (which you prob should, it’s a really interesting class), this supplement is also a staple for that class. (Also, I recommend getting the most recent versions of each supplement—another version won’t come out before you take the class (even the crim pro one, even if you wait till 3L year to take Crim Pro) and I think it’s much easier to have the most recent version so you don’t learn old law that is now outdated, which is especially important in Con Law and Crim Pro.)
9) Maybe consider getting some books from the “Law Stories” series (e.g., Constitutional Law Stories by Dorf). Skip any of the legal analysis if it gets too in depth and basically read for history and background. This is mostly if you’re just really bored though, since it’s only marginally helpful to know the background info of cases. That said, the background and facts of famous cases can be interesting, and, at least for me, it’s a lot easier to focus on learning and remembering the concepts if I already know what the story of the case is somewhat about.
10) If you really must read an Examples and Explanations, read the Civ Pro one by Glannon. It’s probably the best one and understanding the basics of Civ Pro will help you in reading case law for any of your 1L classes.