Google. Google. Google. Google. Google.
Wiktionary. Wiktionary. Wiktionary. Wiktionary. Wiktionary.
Maybe a movie or two now and then.
Some forum posts.
Magnificent charts of magnificent systems.
Youtube videos + youtube comments
Get a chrome extension that automatically translates a word that you double click on.
*Short version*


For real though,
Many things will, obviously, have good explanations and bad ones. Try not to stress over the bad ones, and expose yourself to as many explanations as possible so you can find the good ones.
I also recommend, when trying to memorize something like all the possible noun forms, to just take it easy and soak it up over time with exposure, rather than sitting down and trying to push it into your brain.
This channel presents 90% of the language in a very concise way.
https://www.youtube.com/channel/UCcq...gPcUW3h2I1BGJg