I started using the Iversen method of writing out the radicals and kanji with their meanings (and reading for kanji) when I reached level 11 after looking ahead and realising things were going to be getting complicated on the visual front. If you learn / remember better from writing things down, then it may help you.
And like you, I had not focused as much as I should have on the radicals, but you really need to get them down pat to be able to write out the kanji from memory (I’ve had to tweak or completely rewrite a few mnemonics to remember the correct order).
It does take more time, but that is then time saved by being more accurate in my reviews.