“Themes are the hardest part of the construction process. Filling the grid and writing the clues takes perseverance, but coming up with a theme requires that elusive spark of inspiration.” — constructor Doug Peterson

This sentiment was echoed by other constructors I spoke with. Crossword guru Eileen Saunders said, “The hardest part of constructing a puzzle (for me) is coming with the theme. After that, everything else seems to fall into place.”

Los Angeles Times Crossword Editor Rich Norris and assistant Patti Varol: “Originality is an important element of a good theme, but sometimes originality means lively themers in a chestnut gimmick or a clever spin on familiar wordplay.

“Originality, themewise, is not always ground-breaking, or innovative, or even original. A good theme always has sparkle, with lively, idiomatic phrases that will resonate with a majority of solvers.”

New York Times Crossword constructor Ian Livengood discusses how to choose theme entries: “Once you think of a potentially good theme, it’s vital to see if something similar has been done before. What’s the point of having databases, right? If the theme looks interesting and relatively new, you must make sure the theme is consistent.

“For example, if you are doing two-word phrases that start with the letter P and you’ve got PLEDGE PIN, PARK PLACE, PLUM PUDDING, PINK PANTHER and … PARAKEET, that’s a problem. The single word breaks the pattern and confuses solvers. So consistancy and freshness is very important.”

Rich and Patti also mentioned consistency and balance as critical elements of a good theme. “One odd entry can ruin an otherwise great idea: a themer that ends with the theme’s key word when all the others begin with it, a stray plural in a set of singular phrases, a noun phrase in a group of verbs, a song title in a set of movie titles, a rhyming pun in the mix with spelling-change puns.”

I think I’ll give Doug the final word on coming up with a theme for your puzzle. “If you think a theme entry is humdrum or doesn’t quite fit with the others, it’s time to put your brainstorming cap back on. Remember, your first job is to entertain the solver, so make that theme sparkle.”