Learn by heart and be able to name all of the fallacies used in conversation, there are about 200 of them used every day. Practice spotting them on tv, radio and in conversation. Humans are remarkably illogical, knowing the names of every fallacy helps, commit all of these to memory:

http://en.wikipedia.org/wiki/List_of_fallacies

http://en.wikipedia.org/wiki/List_of_cognitive_biases