I don't sell or collect comic books, but I read your guide all the way thorugh. It is excellent in nearly every regard, and all its general points would be helpful to anyone selling anything on eBay.
I have only one caveat, and that is with this: "eBay allows you to set a starting bid and a reserve price. If you set the starting bid too high, you may discourage people from ever bidding in the first place, so start low and aim high."
Sellers should be aware that (a) the fee for running a reserve auction if hefty and (b) that hefty fee must be paid whether or not the item sells. eBay did that to discourage reserve auctions. Buyers hate reserves and will often hit the back button as soon as they see the word. Or they will will nibble- and sport-bid just to disclose the reserve and then back out of the transaction.
So, better advice is, I believe, to make the opening bid the least amount the seller is willing to take for the comic.
I believe the best advice for new sellers is to not run auctions at all but sell at fixed price, immediate payment required, no offers. I won't go into detail here but you can find plenty of commentary on the Sellers forum to the effect that new sellers are scam magnets, and they are are more likely to be targeted when they run auctions.
But, as I said, your guide is really very good. It's clearly written, logically organized, nicely laid out. I hope potential comics sellers find it.
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