Please forgive me first of all for using the guide title as an example to introduce one of several major problems on ebay: Misleading Titles.  Over half of my communication with ebay is in reporting titles that are exaggerated or otherwise untrue.  There are several areas that dishonest sellers attempt to beguile seasoned and new ebayers alike.

Nintendo DS lite with 11 Games! - the exaggerated title. 

Very often when searching for a specific item, I see something that is too good to be true.  While trying to buy a DS lite recently I came across dozens of auctions that claimed to include a new system with 11 games.  When I opened up the auctions, however, I found what I had guessed to begin with: Rayman DS and a lousy retro collection that contained 10 minigames on one cartridge.  One auction was listed under DS lite and even had DS pre-filled information; but the auction was for a much older system.    

XBOX 360 Buy-It-Now 199.99! - the fraudulent title

A scam artist is one of your worst, most intelligent enemies on the internet.  If they have a stolen item to sell, or no item at all, they will list the item low enough to make you rush to buy the item, but high enough to be remotely reasonable.  I recently was scammed on a lot of 6 rare and sealed Super Nintendo games, that I later found were already being sold by someone else.  I used the buy-it-now to pay someone in Great Britain $165 for an item that never existed - it had been copied exactly, down to the picture and exact description.  At this moment I have over $250 tied up in paypal claims.  And at this point I would rather do 5 minutes of research and lose an item than suffer a greater hassle.

The proverbial Thousand Words. . . - picture pros and cons

Two things about pictures.  1) The auction should have some.  At least one.  Anything worth over $20 is worth taking the time to put up a picture - the first one is free to include anyways!  Questionable sellers will go through the trouble to copy a generic picture but refuse to insert a legitimate one.  2)However, even real-looking pictures can easily be copied.  Do an exact search of the item you want to buy, including title and description.  You may find what I did: a completely copied listing; only I found it after I had paid a lot of money to a thief 3,000 miles away.

"What's in a name?"

Feedback is one of the best ways to tell whether an item could bless or bite you.  A great question to ask is: What does the seller have to lose by robbing you?  Sellers with little or no feedback have nothing to lose by treating you poorly.  They aren't committed to ebay, and have no reputation to lose.  Also, though, sellers with tens of thousands of feedback would not be hurt by mistreating you - you are merely a number; your negative feedback would not hurt them.  And your item may get lost in their large warehouse.  And oversees sellers are often out of sight, and your concerns out of their mind. 

Pay attention to the last time a seller received positive feedback.  If they have not sold anything for months, someone may be hijacking their account to sell nonexistent items.

My shameless plug for hating shipping gougers. . .

I have shipped hundreds of video games.  The average price to ship a gameboy cartridge is 63 cents.  A Nintendo 64 game can be shipped for about $1.12.  And anything smaller than a three-ring binder, no matter the weight, can be shipped for $4.05 in a flat rate Priority Mail envelope.  I charge $2 for First Class Mail and $4 for Priority Mail, which small number more than covers my packaging and handling.  Larger items shipped through UPS are also inexpensive, because UPS ships by size, not weight.  And UPS packages are AUTOMATICALLY  insured for $100.  Games and small accessories do not cost 7.99 or 12.99 to ship.  This is shipping gouging, which we all must continue to report. 

If ebay were a referee . . .

Ebay's policy on fraud sometimes seems like a "no blood, no foul" situation.  But Ebay will never overreact and run to your aid because you, or I, were dumb enough to buy something from a liar or scammer.  Your own tact, discernment, and healthy skepticism are your best defense against fraud.  But you can ALWAYS REPORT an item by clicking on the report this item link at the bottom of a listing.  And you can always fill out a Paypal claim if you only buy from sellers who offer Paypal buyer protection.  And finally, Care.  Care enough to protect yourself.  Care enough to make ebay a better place for those increasingly few of us who want to do things honestly.