An argument, in the logical sense, is a set of premises offered in support of a conclusion. That's it. It isn't a fight, and it isn't a strongly-held opinion stated loudly. If someone says 'immigration is good' and someone else says 'immigration is bad,' no arguments have been made — just two conclusions with no supporting structure.
Once you can see the structure, you get two independent ways to disagree, and confusing them wastes enormous time. You can challenge whether the premises are true, or whether the conclusion actually follows from them even if they are. An argument can be perfectly logical and still worthless because a premise is false; an argument can have all-true premises and still fail because the conclusion doesn't follow. The single most useful habit in reasoning is asking, out loud: what exactly is the claim, and what exactly is supposed to support it?