Make sure you are doing your reviews in time and do at least a set of 5 lessons every day (more when you feel the amount of reviews is too easy).
The reason to do your reviews on time:
When the progression is 4 hours, 8 hours, 24 hours and you do your reviews on time it takes you 4+8+24 = 34 hours to reach Guru.
When you only review once a day it takes you (at worst):
24+24+24 = 72 hours (3 days) to reach Guru (for one item)
If you feel like you want to learn the “meaning” of more Kanji faster you can try Heisig’s Remember the Kanji (RTK). That is what I am doing at the same time. You don’t learn any readings or vocab, so the number of kanji you can learn per day is higher. You need to set up something like Anki for reviews though.
And in WaniKani the kanji you learn are usually somewhat frequently used Kanji. Heisig doesn’t really care about how useful a kanji is, so you also learn kanjis that you might not need for a long time. As a graphical indication (green is Heisig, others WaniKani, ordering by JLPT level (ca.)):
Learning more kanji with Heisig only “helps” in the short run, as you need to learn the readings later anyways.
EDIT: I am also lvl 3, but I started 20th of March (known Hiragan and Katakana before though)

… I was using the Kanken books for learning the readings as well, and I also like those books.

Let’s see.