I haven't read meathead123's book but here is my Short List after researching hundreds of sellers and thousands of listings.
Don't believe any attachments that contradict 3rd party tool results. Seller attachments should re-enforce 3rd party tool statistics, not contradict them. What the hell am I talking about?
1.) Alexa that shows unranked for a domain means the website has no traffic. I don't give a damn what attachments the seller put on the listing. Alexa over 20 million means it has less than 20 visitors a day. Don't try to figure out how Alexa numbers relate to real traffic just know Alexa 0 means no traffic.
2.) Ignore all "potential" claims. All are BS.
3.) Ignore reason for selling site. All are lies and most are getting pathetic. One seller says his kid has cancer and needs an operation as his reason for peddling template websites with fraudulent numbers and lies. I only wish Karma would pay him a visit quick.
4.) Learn Flippa site rules. If a seller is violating rules, don't bid. Here is the rules list I watch and you'll find 70% of listings violate one or more of these 3 rules;
a. No Potential Traffic or Revenue Claims are Allowed in the Title - EVER
b. If the site has earned less than 2 months of revenue (less than 2 mos old) then NO CLAIMS of revenue are allowed in the title or description. It doesn't matter how many fake paypal screenshots the seller posts. Unless a site is more than 2 months old it CAN'T have 2 mos of revenue so any claim violates Flippa rules.
c. Fake aged domain claims in the title or description. In January this year, Flippa revised their domain age claim rule and, in essence, it says domain age is calculated from the time the website in it's current form went live. You will see many listings where sellers are picking up dropped and auction domains, tossing a template website on it and claiming revenue and traffic for a period they weren't even the owner of the website. I'll discuss more a bit later how to bust these idiots.
4.) Pass on any website that has "claimed" traffic or revenue with nothing but non-descript screenshots. PayPal screenshots not showing anything but dollar amounts are all fake. If a seller is serious they'll have screenshots with urls, dates, paypal email address, balance and all the details except buyer's names showing. Pass on any listing just show awstats unless it's cheap enough. Template sellers typically don't ask a lot of money and don't offer detailed analytics. Just buy those sites as no traffic sites.
5.) Learn to read Alexa data, how to find the source of traffic, audience, how percentage of traffic is from search engines. Again, 3rd party tools should re-enforce seller's screenshots. If the seller has a description that says organic traffic and Alexa says less than 1% of the traffic is from search engines then you know the seller is a damn liar.
6.) Always look at the wayback machine to see if archive.org has screenshots of the website from years past. Many times you can see the website before the current seller owned it and rebuff his claim of being an owner for years with his new template.
7.) ALWAYS look at the Google Analytics PDF file. A common trick on Flippa is to claim a high number of visitors and then attach a Google Verified PDF that completely contradicts the Verified Traffic Details in the right sidebar. I've seen sellers post verified analytics saying they get 1000 visitors a month and then opened the verified GA PDF file to see the file says they get 3-5 visitors a day. Don't be fooled by the Verified Traffic Box is the point. Those numbers are entered by the seller.
8.) ALWAYS look at the seller's account for linked accounts and feedback. Don't believe any BS about those linked accounts the seller offers. If those suspended or banned linked accounts weren't valid the seller would of bitched until they were removed. Consider all of them valid and this seller is owner of those accounts.
Ok, I'm out of time. Last trick. Get yourself a domaintools.com free account for 7 days. They take all the CC info but you really can use it for 7 days and cancel without being charged. Before you spend any serious money on a website you look up that domain and check it's history. See if the seller is being truthful or doing like one member here did last night when he stepped on his dick (Kingt***) and claimed a website was his for a year before someone contacted the real owner and had him post on the auction he owned the website until June this year and why is this seller claiming he owned it when he didn't. You'll see all that BS with a paid version of domaintools. If you're buying websites for serious money you're a fool not to own this tool and know a domain's history.
Ok my short list is longer than I planned. No time for proof-reading so ignore the errors please.