1. Is the trick/trap sane or insane? i.e. Is this an actual security system or testing device or whatever that a rational actor would employ?
1a If yes, who put it there?
1b If no, is it a trick or a trap? i.e is there a possible reward, or does it just hurt people?
2. What's the general atmosphere here? Spooky with organic components like living spider webs or is it one of those lever/button kinda setups or occulty circle-of-salt-around-a-demon or what?
3. Is this going to be one of those paranoia things where the real action is not the danger itself but rather all the stuff the PCs have to do to try to detect the trap? If so, do you need to do anything to let the PCs know there might be some kind of trick or trap going on here to get them paranoid? Because if you don't then they will probably just fall into it and it won't be any more interesting than a non-custom designed "hey-I-checked-for-traps-did-I-find-it?" garden-variety trap.
4. Is it going to be one of those things where the obvious randomness is part of the fun? Like "Oh, you walked through the door, roll d6..." In which case, how will you set it up so that it'll get used more than once so that the fun of the randomness actually is on display to the PCs?
5. Can it be reversible? Like can the PCs "use" it in some obvious way? If so, can it just be something really simple that work in conjunction with other parts of the dungeon?
6. Will common sense be rewarded?
7. Will boldness be rewarded?
8. If you went ahead and made it make no sense after question 1, then, now that you've made it, do you want to retroactively go back and find some reason it actually does make sense?
8a. If so, does that imply anything else about the dungeon you can use?
9. If it's a rational security system, why is it so weird? Can the fact that the trap designer had limited resources explain it? Did they expect a different kind of intruder? etc...
10. Did any of that help?
11. Is the only solution some totally obscure fucking arbitrary thing?
11a. If so, is Kimberly playing?
11b. If Kimberly is playing, how are you going to keep her from gouging everyone's eyes out with frustration while they run around trying to find the totally obscure fucking thing?
11c. Should there be a clue? Should the clue be some insane-wizard arbitrarily-placed-there clue "Like 'Roses are red, violets are blue, copper bumblebees like to screw" or should it be something that could end up there by rational means (i.e. a note found scrawled on the body of a dead adventurer in another room)
12. What about illusions? Have you thought about that, Zak?
13. What about feedback-loop-consequences? i.e. failure to do it results in not death but escalating entertaining inconveniences?
14. What about hands-on problems: like "Here's a maze, solve this maze in 12 real-time seconds or die"?
15. Can I kinda make it half-good, but then throw a monster into this room and jsut let the PCs monster, and trick/trap interact in some crazy way for a while?
16. I'm hungry.
17. Ok, really, really, this will be the best trick/trap room ever, Think, Dammit!
18. Is it possible to design this trick/trap such that it will affect the PCs yet they will never know it because they--more or less by sheer luck--did the right thing? If so, do you want to change that,or just let it go?
19. Did you think of something yet? If not, grab a book off the shelf and start reading...
20. Whoa, I didn't know we still had this. Oh look, I underlined something here..."...within that complex of nylon and starched cotton lay a large inert nipple, its pink face crushed by the scented fabrics..."
21. Wait, I'm supposed to be making a trap here. Ok, let's say they go into the room and there's this pink face and it's crushed and...is this going anywhere?
21a. If no, return to 1.
Keep me caffeinated by buying me coffee...
6 hours ago