After reading about quizbowl, you might expect difficulty (specifically, pyramidal difficulty) to be the most important ingredient for a high-quality quizbowl question. However, this is not the case. There are perhaps three elements of a question that are more important to get right than difficulty. You can remember these elements by the acronym NSC (which also happens to be the acronym for the National Scholastic Championship).
Every clue in a quizbowl question should be information that someone in your target audience has a reasonable chance of knowing. If you are certain that no players will know a particular clue, then that clue should not be in your question set. This is because a clue that no one knows is also a clue that will not differentiate anyone's knowledge.
Furthermore, the clues that you choose should be relevant to the subject of the question. Let's go back to the George Washington example. It is true that George Washington had a dog named Madame Moose. It is also true that some high schoolers may know this information. However, if you are writing your George Washington question in the "American History" category, then this would not be a good choice. The names of George Washington's pets may be relevant biographical information, but that does not mean they are relevant to the study of American history as a whole. This would change, however, if you were writing a question on presidential pets! The scope of your question should be determined by the distribution.
A great example of how question scope influences notability is Alexander Borodin, who was famous for careers in both classical music and organic chemistry. Even though both of these subject areas are "academically relevant", it would still be poor form to clue both aspects of Borodin's career in a standard packet. This is because it would mess with the standard amount of "pure history" and "pure science" in the round. It would also make the question worse: with clues jumping between classical music and history, it would either be 1) difficult to follow or 2) obviously referring to the most notable dual composer-chemist. But again, this would change if you set aside a distribution for people who were famous for achievements in two different fields! Again, distribution should determine scope, not the other way around.
If this is a bit too abstract, it can help to think of the word "newsworthy" instead. Let's go back to the newspaper article example. Even though the facts that come up later in a newspaper article are less foundational to the subject of the article, they are stil newsworthy. If a fact wasn't newsworthy, then it wouldn't be taking up limited space in the newspaper at all! So before you write anything, consider whether it is "fit to print"! Every clue should have nontrivial importance to the subject that you are writing about.
Since quizbowl questions are designed to be answered with limited information, every clue should be specific enough to refer to just one answer on its own. Consider the clue "This artist painted The Large Bathers.". This clue may seem fine on its own, but it fails because there are two painters with a famous Large Bathers: Paul Cezanne and Pierre-Auguste Renoir! This creates real problems during matches, as players can be led astray through no fault of their own. Because of this, some extra uniquely identifying information should be added to let players know what the question is looking for.
A revised clue might look something like this: "Besides A Modern Olympia, he painted trees forming a triangle above a group of nude women in The Large Bathers." [2012 PACE NSC]. In this variation, the ambiguity has been removed by the addition of contextual details. Other question writers simply remove the ambiguity directly: "It's not Pierre-Auguste Renoir, but this artist painted The Large Bathers.". These methods are usually necessary for creating a high quality question set, and foreseeing ambiguity is important for running a tournament smoothly and avoiding the anger of misled players.
A good question writer will also include prompts to resolve specificity issues, and protests are always available as a last resort. But while prompts and protests do a lot to address ambiguity, they cannot completely cover up sloppy question writing! Questions must always be written with specificity in mind.
The most important quality of all is coherence: your question needs to make sense! Question writers often tie themselves into knots while trying to make their question uniquely identifying or point to an unnatural answer. The more complicated a question's wording is, the more difficult it is to figure out the answer at game speed. Make sure all questions are read in full before they are played! If your question cannot be understood, then none of the other elements will matter!
There are more important things than difficulty when it comes to writing quizbowl questions. But that doesn't mean difficulty doesn't matter! We'll talk about managing difficulty in Part II: Difficulty.