[Epistemic Status: Request for Proposal]
For anyone who is familiar with CFAR's teaching program, the concept of the TAP will be very familiar. It's an acronym that expands either to Trigger-Action Pattern (for naturally-occurring instances) or Trigger-Action Plan (for purposefully-implemented instances); the latter is known academically as "implementation intentions". While there is room for contest for the title of "Most Important CFAR Skill" in terms of which one has the most impact of regular use, in terms of driving adoption of techniques, TAPs are the foundation of the entire curriculum. From simple skills to complex ones, the default flow of practicing a skill is "install a TAP to practice this", and the default call to action of most CFAR classes is "spend five minutes brainstorming TAPs to install".
They're extremely useful...if they work at all.
For me, they don't. I struggled to find any example at all of a trigger-action patterns in my own life, and even following the extreme repetition, hard-mode path to installing a TAP, found that it vanished as soon as I stopped consciously thinking about keeping it up.
I liked most of the techniques I learned at my workshop. Many seemed quite useful to apply. I remember approximately none of them, because, deprived of the core tool to maintain them, every piece of practice looked like

It's a strong foundation, for most people. But it's still a foundation; if it doesn't hold, nothing else is any use. So:
What other things have people devised to turn a technique from a sketch of ideas to something used often enough that it's a proper skill?
As a starting point, things that I use in my particular case:
Calendar reminders.
These are all reasonably good at their particular, time-based niches. But none of them work well for irregularly-occurring opportunities or for fuzzier, less specific types of practice.
An alternate question, which seems to me to be similar in applicability, is:
How would you build a daily or weekly routine from scratch, with literally no existing example to piggyback on?
>When you go to the bathroom, and you fail to execute the "look at the waterflosser" thing, what do you do instead? Do you look somewhere else?
I look whichever direction I'm moving. Or I stare blankly while I think of something else. Or I look at the clock, which technically requires turning to look past the waterflosser but did not involve the flosser registering to my attention. Whatever was in line with what I was doing/thinking about before walking in.
>What happens when you put a sign on the door saying "remember the waterflosser?"
Never tried. No longer live there, but I could attempt something like it.
>What happens if the waterflosser is right next to whatever it is you most frequently need to do in the bathroom? Do you use the sink regularly?
It was and I did, and so I usually had my gaze wander to it while I was in the bathroom at some point. Probably 80% of the time. This usually meant that I'd remember to use it if I hadn't already that day.
>Do you brush your teeth? (If so, then it seems like somehow somewhere you got a habit of doing that - how did that happen?)
Yes. I have a Beeminder goal for it (this is my "anchor" goal that I need to update almost every day, which will ping me with a phone notification if I miss more than a couple days, or more often forget to enter my data for a couple days). Most mornings I remember before I leave the house. I also keep a travel brush in my backpack and another at work, for the mornings when I don't. (Somewhere between 1/3-1/4 of weekday mornings. Weekends it's more like 80%.) Evenings I almost always think of it while I'm winding down for the night, probably 90% of the time, unless there is a distraction like a visiting guest.
I think I had it as part of a routine when I was a kid, and definitely had an ironclad morning routine during my first internship, during high school, which included a shower and brushing my teeth. Before having this goal I think I remembered to brush my teeth about once every two days.
>What is "remembering to eat" like? (it seems like you must at least successfully do that most days)
You'd think! But no, not really. (If I rated the problems in my life right now by (tractability x impact) this would win.) I generally will not think about eating until my stomach hurts from hunger. Sometimes that passes and I forget about it before I have pulled myself away from whatever mildly interesting activity I'm doing. If that happens, and it doesn't reoccur, then I will probably not think of it again until I notice my movements and thoughts becoming sluggish from lack of energy. (On one occasion, now years ago and thankfully unrepeated, I continued this for about 48 hours over a Thanksgiving Weekend, consuming only water and half a bag of stale Chex Mix. It was a bad time.)
To mitigate this problem I try to keep a lot of extremely low-effort food around - yogurt drinks in the fridge, large cans of cashews on my bedside shelves, and when I noticed myself losing energy, eating some of those and then trying to get up to make something slightly more substantial like a couple PB&Js. Despite this accommodations and willingness to order takeout, I think I've averaged about 1.8 meals a day over the last two months of weekends, much of them taken as grazing just enough to keep me not collapsing.
Luckily food at Google comes free and pre-cooked into convenient forms that require only walking, no thinking. And I am doing enough attention-intensive activities that I notice much sooner that my function is impaired, so I intervene before I start losing the ability to move or act like a person.