Memorizing Kanji

Take a look at this post - [Userscript] Self-Study Quiz
It explains in detail how to use it.

Essentially, if you notice that you are failing to identify a specific word again and again (these words are “leeches”) you can use this script to study those leeches in particular. Or if you just want to study the words which failed their last review, you can do that too. There are a ton of options besides these two.