What are at least TWO ways to assess the credibility of an argument?

1) Are any specific facts cited? If not, then the argument may be true but it lacks any cited evidence, making it weak.
2) If supposed facts are cited, research them for veracity. Use multiple sources, none of which are known to be funded by political partisans, i.e. Soros-funded Wikipedia that is often great but falls down on many topics that could be considered to be political in some sense.