Frequent references to WP:AGF are a sure sign a user is in good faith.
Frequent references to WP:NPA are a sure sign a user cares deeply about politeness and are themselves very courteous.
If a person edits Wikipedia largely or solely to promote one side of a contentious issue, they're likely to have spent years of their life studying it. Therefore they're almost certainly an asset to the project.
Patriotism is a virtue. Wikipedia needs to encourage virtuous people to edit as much as possible here, especially to add material about their own country.
The best way to make established users more civil is to block them for a while. (Ask an admin to do it if you're not one yourself.) In the rare cases where that doesn't help,[1] you can try putting a civility template on their page, or telling them about the policy WP:CIV, which they may not be aware of.
When people insist that before blocked users can be unblocked, they must apologise, admit their mistakes, agree to learn to avoid previous pitfalls, work to address all of the issues, pave the road, seek redemption, face the music, show that they understand why exactly they were blocked and how right it was that they should be, or show remorse, it's probably not because the insister would like to see a show trial or ritual humiliation.[2] More likely they have some psychiatric training and know how important it is to resolve conflicts and seek reconciliation, and how much better the delinquent would feel afterwards.
The use of WP:ROPE in a discussion simply means the user wants to give somebody a second chance, not that they enjoy invoking violent metaphors or are out to ambush somebody.
The use of WP:STICK in a discussion means the user didn't want to bore the reader with all the good arguments they could have added.
The use of WP:OWN in a discussion doesn't mean the user is all out of real arguments for the version they prefer, it simply means… hmm. Working on that one.
It's good to add a touch of humour to discussions that are threatening to get heated. For instance, references to WP:TROUT will make everybody laugh, thus defusing bad situations.
"Enforcer" phrases such as The facts are the facts, It's that simple, End of discussion, Simple as that, and Period will add force and truthiness to any statement in any Wikipedia discussion.[3]