I don’t think I did this until I started approaching level 40, but eventually I started using the Double Check script to force correct answers on ALL Apprentice items. It prevented me from getting completely overwhelmed by the same few terms over and over and over, and instead got me used to them over a slightly longer period of time.
Fewer total reviews (for a given day), fewer repeats, less frustration.
Always a feeling of progress this way 
Two tips
誰があんたをトンカトラックに化かした?
古いプロフィールの写真がもっと大好きだった。
* Prays that made sense * xD
I’m nearing the end of the death levels so my experience is fresh. Hopefully this will help!
Mnemonics, mnemonics, mnemonics. To be completely honest, I don’t always use the mnemonics provided by WaniKani; I often make up my own if theirs is a little bit too complex for me/hard to remember. But using one as a shortcut has saved my hide a few times!
Don’t be afraid to make mistakes. It hurts to miss the one kanji that’ll let you level up, but it’s worth it in the long run. My longest levels have been here in the death zone but that’s okay! Take the extra time to really nail down those kanji.
For those kanji that I constantly mix up, I have them physically written down side by side with their readings and sample vocabulary. Having them in once place makes it easier for me to notice the differences. There will be a lot that look really similar to each other as you go, so pay special attention to the radicals in each one. I take a quick glance at them at the end of the day just to remind myself of the differences.
頑張って！
Since latter half of Painful and now in Death levels, I’ve been making my own mnemonics because WK mnemonics are just very abstract and long. I used not to make my own in earlier levels, but I drop a lot in Apprentice recently because WK mnemonics just don’t stick much as my own.
Another useful tool for this is this script: [Userscript] ConfusionGuesser which tries to guess why you got something wrong. It’s not always right, but if you put in a reading that’s actually for a similar-looking kanji, it’ll usually be able to tell you that. (Very handy for those moments where you know you gave the answer because it was for something else similar but you can’t remember what!) Doesn’t obviate the benefit of drawing similar kanji out on paper, but it can definitely point out kanji you didn’t realize were similar/you were confusing (as well as other types of confusions)!
One of my biggest trip-ups with the death levels has been all the 訓読み (especially all these verbs…). Either there’s been more of them or there’s been more of them I didn’t already know, and most of them trip me up! So many long-form stories, and most of them for a unique string of syllables (unlike readings that can tie into now-familiar objects like tater tots and ray guns), and almost none of them tied directly to the story tying the radicals to the meaning. Anyone got tips for that part?
Also offering moral support and comradry in our sufferings. I have found that death has all but killed me. I’ve almost given up many times… It’s really tough.
I’m stuck in the middle of the valley of death and contemplating a reset to 21 or so. If I go back, I will focus more on distinguishing the words that WK says are synonyms. I have also started studying offline using Quizlet. Reading and listening (detective JDramas for me) helps a lot too. A lot of the vocab pops up in JDramas e.g crime, guilt, police stuff etc. I would love to find these with JP subtitles.
Mnemonics are great but the WK ones are basically useless to me … making up my own takes a lot of time but is worth the effort.
I’m just here for the advice and to express how relieved I am that I’m not the only one. I feel like my kanji knowledge has overtaken my Japanese knowledge to the point where I’m not sure I could read texts with these kanji in them…
taking breaks from lessons is a good thing, I stayed on level 20 for 50 days, for 21 I took it easy at 15 days, and now I’m back to going fast like an idiot
I am not a truck, am a cat!
I did just that, resetting from 24 to 20 and its been the best decision for me. Much better experience now. I‘d say do it!
I am at the end of death atm (lv 30) and I can assure you, wanikani has killed me these past few levels 
Wow that sounds like a good idea… Just doing it for apprentice makes sure that you wont burn something you dont know, and I agree on getting overwhelmed by them, I have around 280 and im dying from reviews. May the crabigator save my soul
And you’d stop after apprentice? Did you find you would get them wrong and drop them back down to apprentice?
Nope. I still get 加える and 貯える wrong often.
But maybe, yes? Say them out loud a bunch or something. Review them outside of scheduled reviews. Listen to the audio like twelve times while staring at the word.
Re: Forcing correct answers on all Apprentice items
Yeah. Note though, that because an item at Guru 1 drops to Apprentice 3, all this does is prevent items from falling to Apprentice 1 (review in 4 hours) and Apprentice 2 (review in 8 hours). It’s still the same SRS system, just with a slightly higher “minimum” SRS level.
So, when I failed a G1 review:
G1 → A3 (next review in 1 day)
A3 → A4 (next review in 2 days)
A4 → G1 (next review in 7 days)
After those 7 days, when it’d resurface at G1 again, there’s a high chance I’d get it right. Even If I got it wrong though, it’d just repeat the same process for another week.
It was definitely worth it for all the frustration it saved me, because nothing’s more frustrating/demotivating during these reviews than having to answer the same few items ad nauseam.
What would you say is the big difference in difficulty in the higher levels?
Is it the amount of reviews that have stacked up for each level until that point, or that the words are less tangible?
What do I have to look forward to? 
Reviews are a part of it, but stupid words that don’t make any sense using the kanji meaning, those are a pain
Basically what @Loglog74 said. It’s weird because we start having semi-synonym words or just vague ones, like another word for “duty”, the words for “matter”, another word for “plan”, the word for “examine” kind of looks like the kanji used in the word for “test” and they even have the same reading, but like a lot of times I’m seeing 3-radical kanji that share two radicals (or 4-radical kanji that share 3) and it gets CONFUSING