Trading with Dealers at Card Shows?

[sonnyu2]

Briefly, whats the best way to approach a trade with a dealer?
Ask if the dealer is willing to trade. Some will, some won't. Trading is cumbersome and many dealers will decline unless you have something they really want.

What should I expect in terms of value of my cards in a trade?
Really depends on what cards they are and their value. The more desirable and valuable a card is, the more you will get in trade value. If it is common lower-value stuff you may not get much value and/or interest in a trade.

What "book" values are most commonly used?
There are not many dealers that use book values these days. Majority will go by recent comps of actual sales.

Any specific signs to recognize in dealers dealing a trade fairly?...not so fairly?
No way of knowing until you attempt a trade. Trading is a two-way street. Just don't agree to trade if the terms don't seem fair to you.

Biggest advice is to come prepared with what you value your cards at. That will help save a ton of time when negotiating a trade.