There's really too many things to mention about case list preparation. Some basics, though, are pretty much common sense. Keep up with your cases, be as brief as possible when making your list ("weed out" the unnecessary/irrelevant information), don't wait until the last minute, make multiple revisions (this is not the time to save trees), have your list reviewed by "experienced" people, and by all means DO NOT LIE.
There are several resources out there to help you in your preparations, including a somewhat useful Oral Boards Prep book by Anita Krishna Das (available on amazon.com), several prep courses (Dr. Wall, Exampro, Osler, etc), mentors at your old residency program, and colleagues that have recently presented the Oral Boards. Be selective in who you go to for advice and be prepared to hear a variety of differing opinions. In the end and despite which resources you use, it will ultimately be only your efforts that will make or break your list. Case list prep courses are by no means a "must", but they are indeed extremely helpful in getting an experienced perspective on how to perfect your list. I definitely recommend them if you have the time and means to attend.
Once you are done, make sure you submit a flawless list. Make sure that all typos and grammatical/spelling errors are eliminated and that all used abbreviations are approved by ABOG (a list of these is provided on their website and in their Oral Boards pamphlet). Remember that your list represents you and how you practice and that it provides a "first impression" to your examiners. A poorly or carelessly constructed list can easily put your examiners in a bad mood before they even meet you. Contrary to popular belief, a great list will not pass you. A poor one, however, can set you up for failure.
There are many more things to mention, but not enough time to address all of them. Make sure you continue to ask around and good luck with your collection.