Constructor's CommentsMy approach when constructing a themeless puzzle is to create a puzzle that feels enjoyable to solve—a bit of a struggle, perhaps, but ultimately conquerable by most solvers.
To that end, I try to pick an open grid design with good flow throughout—one that allows the solver multiple points to tackle stubborn sections while they solve.
I started the filling process for this particular grid with the 1-Across entry, since this colorful phrase was fresh in my mind from a recent Family Dinner Night discussion of what makes for a better "scary" movie format: the modern procession of in-your-face JUMP SCARES or the classic prolonged escalation of atmospheric dread and tension. (BTW, the consensus was heavy on the classic with a minimum of JS needed.) Filling step-by-step from this "seed" entry, whenever presented with a choice of what might fit next, I usually opt for using multiword entries, as they tend to be more interesting, and I sprinkle in some scrabbly letters along the way for added zest.
On the what-not-to-use-as-fill side for themeless puzzles, I tend to avoid the use of partials (ON A, UP A, etc.) and abbreviations (MGR, PKG, TSP, etc.). I also struggle hard to avoid using "cheater" squares—those extra black squares in the corners that don't affect the word count of a puzzle—when filling a themeless grid because I hate to cheat the solver out of another pair of squares that need filling in.
All these factors tend to increase the challenge of constructing a themeless puzzle, yet I think the solver usually benefits from a smoother and more consistently enjoyable solve. At least, that's what I keep telling myself—enjoy :)!