How to Debate an Evolutionist?
I'd say the best way is to use current data, and consider the entire body of evidence.Using appeals of authority to statements made by scientists and texts from a few decades back or positions that are selectively "evidence based" isn't entirely persuasive.
Evolution (what is being debated) is essentiallly a naturalistic version of history
This definition should be brought out early. Since it is in a sense a reasonable statement it should be easy to get people to agree to what its saying....then build from there to try and contrast history and science....ergo evolution is not scientific. Of course the definition must be broad and not minimalist (i.e. changes in allele frequencies) so that any uncertainty in some fields of research like abiogenesis can be harped upon to try and discredit the whole concept.
Do you see why its important to be insistent on certain definitions? Otherwise the whole house of cards topples. Great debaters aren't necessarily more accurate than others..just more adept at trying to make the other side's argument appear weakly based.