Additions a local came up with.

28) There is no such thing as a road mountain bike
29) Just because you are selling it for a friend doesn't make you an expert if you are not
30) If you don't list the brand and it is unreadable in the photos, we will assume it is a POS
31) Research the going price of your bike before posting
32) Just because it cost a lot 10 years ago when it was brand new and you have barely rode it, doesn't mean it is worth 50% + of new price (see #31)
33) Just because you bought it within the past year doesn't mean someone is going to pay close to what you paid, especially if the new model years are coming out and yours is now discounted
34) Don't use terms you do not understand - if it does not have rear suspension, it is not full suspension
35) Proofread - I have never seen a bike measured in feet but I've seen a lot of 26' bikes posted
36) If it is a *mart bike and you just paid to have it "tuned up", you probably just wasted your money as the tune up was probably more than the bike is worth
37) We don't want to call for basic information you should have posted or to have you send us pictures
38) Don't sell a used helmet unless you really did just buy it, otherwise it may have been crashed and is a safety hazard