published advice.

Published in 1997, Flea: The Definitive Guide to Hunting, Gathering, and Flaunting Superior Vintage Wares by Sheila Zubrod & David Stern, provides its' readers with great tips and advice on how to approach a flea market. While a bit outdated in regards to the state by state listing of markets, the book is filled with tidbits of useful information when visiting a flea market. 

Chapter 4 - "Basic Survival Skills 101" offers just what the title states. The authors provide some hints that will make you able to sift through the rummage of the flea with easier tactics. Here are just a few of the skills that are listed to bring to the market.

1. Act Nonchalant - Don't make yourself seem needy or desperate for an item.If you do, it's unlikely that the seller will be willing to haggle/give you a cheap price when they know that you really want an item.
2. Bring a Magnet & Magnifying Glass - To tell the cheap metal/iron from the real, use a magnet. A magnet will stick to the cheap stuff but will not stick to bronze, copper, brass, silver, or steel. A magnifying glass can help identify trademarks, dates, names, etc. 
3. Blankets, Bubble Wrap, & Newspaper - These items are good to keep in your car in case you need something to wrap delicate items in. Most sellers do wrap items in newspaper, but some do not. So, you can have your bases covered by bringing your own.
4. "A strategy worth trying if you're even slightly ambivalent about the object in question is to arrive early, find a find, decide if you can live without it although you'd really rather not abandon it, and then return at the end of the day to see if it is still there. If it is, your odds of acquiring the piece for a song greatly increases." (pg.47) 
5. Slow or Busy? - See if it is a slow day at the flea or a busy day. If it's slow, you might have a better chance of getting an item for less than the sticker price. If it's a busy day, the seller might not take your low offer thinking that he/she can get the sticker price from someone else. 

My pieces of advice?

•  Arrive early, but not too early- I've gone to the market earlier than normal one time, only to be walking around while sellers were still setting up. After a few visits to the same market, you'll get the feel of what time is best to arrive in the morning.  
•  Have an idea of what you are willing to pay for an item- If I find an item that I like that is not priced, I set in my mind a certain price that I'm willing to pay & what I won't pay. If the initial price they offer is much higher than what I would pay, I politely decline. I still have to learn the art of the haggle!
• Do your research - For non-serious collectors that have a few favorite items they like to purchase, try and do some research as to determine price points and in some cases, determining age/detecting fakes. If you don't feel like carrying around a book about antique pricing, write hints on notecards or a small piece of paper and carry it in your wallet. Indicate trademarks, what to look for, colors, dates, etc. It will give you some piece of mind that you are getting what you pay for.
• Pack snacks/water bottle - Often markets will have vendors or a central eating place, which can be crowded and even overpriced at times. Bringing a bottle of water and a granola bar makes for more money to spend on finds and less time waiting in line to purchase a can of soda. 
• More to follow...

~Flea Fact~

Be prepared. It is easy to get overwhelmed once you are amongst boxes of unknown possibilities.