I noticed that was true for me in the first few levels as well. Two things that helped immensely are:
- Reading appropriate level Japanese material every day
- Doing KaniWani alongside WaniKani which forces production of the things you learn on WK since WK only covers recognition. That in turn helps move them into your active vocabulary instead of just being in your passive vocab.
As for reading, I started with graded readers and other absolute beginner things like:
- Some of free N5 resources listed one the Dokushu Bookclub site
- Notably, the Tadoku Level 0 Free Graded Readers
- The beginner material on YomuYomu
Then, I moved on to Satori Reader which is paid, but has been an excellent resource well worth the money for me. There is a Satori Reader Appreciation Thread here on the WK forums if you think you might be interested in reading a bit more about that.