There are many worthy questions that need to be answered concerning the reckoned age of the earth.  The problem is that those who subscribe to an old earth can be quite evasive.  Often credentials of the questioner become the issue rather than the evidence that spawned the question.  Perhaps this is because there is not a good answer to those particular questions.

A cousin to the previous tactic is to characterize the young earth position in a way that makes it easier to dismiss or to attack.  By stereo-typing people, attention can be diverted from a weak position and credibility can be sapped from a strong one.

Relying on "expert" testimony can be nothing more than an opportunity to reinforce a particular bias.  Worthy experts will admit their bias up front, beware of the expert who says he is unbiased.

Watch out for poorly defined terms.  They lead to bait and switch tactics.  Be sure that evolution is used in the same way at the beginning of a debate as it is at the close of a debate.  Evolution is not the only term to watch for either.

Don't allow an opponent's presuppositions to become the frame of reference.  If something is to be questioned honestly a level playing field insures that responses do not take the questioner to task for asking.

One thing about the question of origins that we all need to observe is whether a theory is testable.  With the fossil record being such a disappointment for the evolutionists, some wild variations on Darwin's theory have been floated.  The problem is that none of them are testable.  Such theories are not really theories at all.  They are better called models.  Dr. Walt Brown has excelled at risking his theories by constructing them so that they are testable.  We should be very suspicious of those who decline to take such risks.

Check websites for these tactics.  As Phillip Johnson, author of "Defeating Darwinism By Opening Minds",  would say, "tune up your baloney detector!"  Once these tactics are identified they no longer intimidate.  Go see for yourself!