I have to admit first 3 months I got no idea what I’m doing. I got the excitement phase at first couple weeks, as it worn off I got slow down. Too lazy to pick up new lessons, got a lot items wrong.
I think what makes my motivation regain is strolling around the community. I found out how to use User Script, thanks to the script author for great works! And in community you can find any information you need, new insight, and pro tips and trick ~
For items that haunting you, I recommend to use [Userscript] Wanikani Item Inspector . So far, I always got items that haunting me, and doesn’t stick easily 
. But as long as you relearn the items, it’s will stick sooner or later ~
* this is a bit embarrassing I failed 切れる (level 3 vocab) for the 5th time, I hope I can sweep all of them soon haha