The tricky thing about publishing through DriveThruCards lately is the absence of a printed rulebook. There are numerous other options, like the link to the rulebook in PDF format on DriveThruCards' site or making it available for download on BGG. This has the advantage of being a "live" set of rules, which can be updated as questions arise.
The average buyer still expects rules with purchase, though. So that means formatting a set of rules that fit on several 2.5" x 3.5" cards, numbered so you can keep them in order while learning the rules. The downside is that once it's in print, it'll be rough PR move to change the deck and explain to previous buyers why their old cards are are faulty.
So, just like in traditional publishing, you gotta look over your rules a lot! Here are the rules for Nine Lives, version 1.0, after extensive review from very industrious Twitter followers. Many thanks to all the people who helped out looking over the rules to make sure it was clear as possible!
Download: 1.9 Meg PDF
As a bit of compromise, I do include a disclaimer on the first page of rules that the rules might be updated later, including a link and QR code to my site. Hopefully this covers all my bases, between a "live" digital document and a static printed document.