"How can you believe this woman; she works for the government!"
The woman's employment may or may not have some bearing on what she is saying, but you should not assume that she is wrong on that basis.
An argument ad populem does the reverse: it assumes that someone is correct because of his or her position:
"If the Premier says so, it must be true."
Again, you should not assume that the Premier is telling the truth.
The appeal to authority is similar, in that it assumes that a prestigious person or document must of necessity be right. Even Aristotle may be wrong about gravity, or the Bible wrong about the circumference of a circle. Especially in literary essays, simply quoting a well-known critic will not of itself support your argument; you must be prepared for the sceptic who will question the pronouncements even of a Northrop Frye.
Name-calling is in a sense the opposite of the appeal to authority: it is the process of placing what the writer dislikes or opposes into a generally odious category without justifying the use of the terms. Conservatives call Liberals "Communists" while Liberals call Conservatives "Fascists." Name-calling appeals to prejudice, not to rationality.
An argument ad misericordiam argues that something is true because if it is not, someone will suffer:
"There must be a solution, because otherwise we will all perish!"
Unfortunately, this is usually not the case.
An appeal to force argues that a statement is true because physical harm will come to those who disagree with it.
The most common fallacy of relevance is the bandwagon argument: "50,000,000 Elvis Fans Can't Be Wrong!" This argument usually provokes the Bridge Question: "If everybody jumped off the Johnson St. Bridge, would you do it too?" Remember that the opinion of the majority is not always the one to accept.