Check for common pitfalls

Is the trigger too broad or too specific, such that the move will trigger more often or less often than you want? If so, fix it.

Does your trigger confound outcome with intent? Have you written "When you solve the puzzle" instead of "When you try to solve the puzzle"? If so, clarify the trigger.

Does your move apply player mechanics to monsters/NPCs? For example, does it say, "Your foe has disadvantage on their next move" or "They mark dazed." Monsters and NPCs don't use those rules! Rewrite the result to impose a fictional limitation, or to grant PCs an opportunity or bonus against it. (It is okay to modify the damage rolls of monsters or NPCs, or to apply modifiers or debilities to followers.)

Does your move refer to "rounds," "turns," or other concepts that don't exist in Stonetop? Use fictional equivalents instead (like "for a few moments," or "until they can clear their head").

Are any of the results boring? Do they amount to "nothing happens," or "try again?" If so, try to restructure the move so that there's a meaningful result or change every time it triggers.

Is the move purely mechanical? Sometimes this makes sense, like with Improved Stat. But most moves should prompt interesting fiction via their triggers and/or generate it via their results.

If the move involves a pick list, are all the options equally appealing (or equally bad)? For each option, can you imagine a time when a player would pick this over one of the others? If not, either make the option more appealing or cut it entirely.

Does the move blatantly cross the Line of GM/player authority? Does it have the player decide what NPCs or other PCs do, or invent new details about the current situation that their PC would have no influence over or prior knowledge of? If so, change what decisions get made, or who makes them.

Is this a playbook or arcanum move, or some other move meant to give the PC an edge? If so, make sure it's actually letting them do something they couldn't do without the move, or letting them do it better. If it's just a more-specific version of Defy Danger, then what's the point?

Is the move overly complex? Does it have too many variations or variables? Does it have a lot of steps or dependencies? If so, simplify it. Rein in its scope if you need to. Cut any decision that isn't crucial. Reorder the procedure so that it flows naturally and intuitively. If need be, split this out into multiple moves.

Is the move written defensively? Does it use legalistic language to prevent abuse or loopholes? If so, does it need to? Can you rely on context and the players' agenda and principles to prevent such abuse? You do sometimes need to clarify intent and establish what a move can't do, but keep it short and sweet.