A bit more advice.
Forget the first row of games, forget them entirely. You can always tell the first row (regardless of where it actually is numerically) because the first row will be almost all 19" games and MOST of the classics will be there. If you see a bunch of A list classics all next to each other, all at the end of the row, then that is the first row.
Forget that row, prices are highest there.
Ok, goodie. Now that you know that. Time for the real stuff.
The second row is usually where all the 25" and 27" games are. If you are gunning for one of these then by all means get a good look at the monitors in ALL of them. You may or may not be able to stand close when they are auctioned, and big monitors are not cheap to replace.
Spend lots of time looking over machines you are interested in. I like to try to check everything I can on machines I am gunning for. On dead games be sure to try and see if there is a board inside. Look through the coin door, if you can. I will also jimmmy the machine forward or over to see the condition of the sideart as well.
Learn to keep your mouth shut when needed. Last auction I went to had a Gunfight cabinet that had been converted to lord knows what (dead, dead, dead). It was basically a turd with a 13" monitor mounted vertically in it. I love black and white games so I examined it closely, I peered inside and spotted a puckman board. I made the mistake of mentioning it to another collector. Anyway, by the time that TURD sold it went for over $100. Had I kept my mouth shut I could have probably had the thing for $5 as it was one of the last games sold, and it was dead, painted brown, etc,etc.
Don't go to sleep during the redemption equipment portion of the auction. Especially if you are on a limited budget, but have lots of space. I have seen all sorts of cool redemption games (usually larger ones) in working order sell for less than $25. Wacky Gators, spinny ticket things, stuff like that.
If your scoping the jap slots you are going to want to buy machines that are roughly 2/3rds of the way down the row. The prices on them are usually lowest at this point in the auction. The prices start way high, slowly come down, then spike at the end again as they run out of them.
Dead gambling games make great mame cabinets and they USUALLY have nice working monitors (with burn in of course), and tend to have boardset and power supply problems instead.
Measure all your doorways before going to the auction. Ask me the story about the Dunk Shot cocktail that sat behind my apartment building under a blanket for weeks.
Do a bit of research on problem games BEFORE going to the auction to avoid buying those hard to fix project games.
Print out this list of games. These are suicide battery games. Best to be avoided altogether. Some are repairable, many aren;t. Best to just avoid them completely.
http://www.arcadecollecting.com/dead/dead.htmlJust print that whole web page and put it in your pocket, so you can tell right away if it is a suicide battery game or not.
Other problem games. Note, these games either have impossible to find parts, fatal flaws, tend to have acid eaten boards, or are just unreliable.
Pole Position 1 and 2
Berzerk
All laserdisc games
Qix
Zookeeper
Domino Man
Journey
Kozmik Krooz'r
Satan's Hollow
Tron
Two Tigers
Wacko
Solar Quest (unique VECTOR monitor).
Assault (no proper replacement joysticks).
Space Firebird if the shot animations are missing.
Every game ever made by Meadows. They are all black and white and NEVER work. No one on the web seems to have a fully working Meadows game.
Every CHD game in mame. Hard drive based games are also unreliable, as the drives wear out and aren't always easy to replace (some are). I'd just avoid them on principle.
Stuff to look for.
Dead black and white games that are in nice shape. Very nice black and white games that don't power up can often be had for almost nothing. From my experience dead black and white games almost always have working monitors, they usually have a boardset problem.
http://www.elektronforge.com/ fixes most black and white game board for around 100 bucks. Might want to print out the list of boards they service and bring it with you.
I will repeat that black and white games almost always have working monitors. To date I have purchased 8 dead black and white games and all 8 of them had working monitors. Note I am talking about raster games here, not vector games like Asteroids.
Finally, team up. Try to locate the other byoac member, or rgvac members, or klov.com members. Stick with them, talk about what you are going for and avoid bidding against each other. It will help each of you get a better deal.