My earlier reply was about notes, but I forgot to mention slumps and motivation.
Everyone goes through slumps but making a habit of daily reviews always got me through mine.
I’ll discuss some motivational tricks below, but in my opinion, the ENTIRE key to success with WK is to consistently perform a comfortable number of reviews almost every single day (ideally getting your review queue down or close to zero each time). Lessons are the “throttle” for the workload, reviews are the workload. Life happens, so don’t beat yourself up if you miss a day or two here and there, but WK works best if you do your reviews every single day. (I’m no speed-runner, so I’ve no interest in more than one session per day.)
“Comfortable” means that it doesn’t feel like a slog. Two things affect my comfort level: the total number of items in my daily review queue, and my accuracy rate (mostly affected by percentage of review items in the Apprentice 1 or Apprentice 2 stages).
Each person is different, but for me, a “comfortable” review session takes about an hour to complete and comprises about 100 to 150 items that I can answer about 85% to 90% of the time.
Seeing under 100 items in the queue feels like a vacation day (woohoo!). 100 to 150 is normal. Seeing 150-200 tells me I’m in for a harder day than usual. I kinda dread seeing much more than 200 in the queue — I usually try to break it into a morning and evening session when I see that many.
Similarly, if I answer more than 92% of the questions in the session correctly it feels like a breeze. 85% to 92% still seems pretty effortless, but normal. 80% to 85% feels kinda hard. Below 80% feels like a demotivating slog.
So I do everything I can to keep the review queue to under 150 and accuracy rates close to 90%. Mostly this means doing just enough lessons to keep around 100 items in the Apprentice bucket.
My Japanese vocabulary was already pretty established (I’ve been trying to learn this crazy language since 1975) so I find vocabulary lessons fun (“So THAT’S the character for that word!”) and easy. I do many more lessons when I’m toward the end of a level because I’ll mostly see friendly purple vocabulary lessons. The beginning of a level is mostly evil pink kanji, so I rarely do more than five a day. (I don’t like seeing more than 5-15 kanji in the Apprentice 1 or Apprentice 2 stages.) Simply put: do more lessons when they seem easy, fewer when they feel hard.
Decide on a time of day that works for you and try to do your reviews at the same time every day. I like mornings because I’m still sharp and unlikely to be interrupted. Many others are night owls. Some people prefer their lunch break.
Try to associate WK reviews with something you do every day. For me, it’s drinking coffee. I do my reviews with my morning coffee every day. I once read that it takes three weeks to form a habit. But anything works: making the bed, brushing your teeth, laying out your clothes for tomorrow, whatever. Just try to do your reviews immediately afterward until the association is formed and it becomes such a habit that you can’t do that thing without at least thinking about WK.
Rewards can also be a good motivator. Give yourself some small treat whenever you do your reviews. A snack or another beverage works well. Maybe giving yourself permission to indulge in a few minutes of web surfing. Anything really. Just don’t reward yourself until you do at least a few reviews that day.
Streak tracking also does wonders. I’m a fan of a physical calendar with a big red X that you enter every day you review at least a few items (ideally getting the queue down to zero). Try to make that string of Xs as long as possible. The game becomes don’t break the chain. The heatmap user script will automate this, and WK itself will track your longest streak, but nothing beats the visceral feeling of crossing out the current day on a physical calendar. Writing that big red X becomes its own reward!
Lastly, try to focus on your successes and never feel guilty about missing a day or struggling with your reviews. Learning to read several thousand kanji and vocabulary items is a tremendous undertaking. Take pride in the progress your making and try not to be too hard on yourself when it inevitably gets harder.
Just. Do. Your. Reviews.™