I've finished the first plurals skill on the Swedish tree a few days ago, and tried to rehearse this every day since I found it quite hard but it doesn't seem to stick with me. No matter how many times I rehearse the skill, I get most of it wrong every time.
It's really annoying me, and I was wondering how you guys learned and remembered it because I have no idea how I'll be able to. Do you have any tips? Should I just rehearse until I get all of it right, or should I learn how to predict the plural by heart?
Reading the notes, reading it in an external grammar book, learning the rules.
Once you know the rules and accept that you basically have to know which of the five groups a noun belongs to it is quite easy. But the excercise will not help you with that, you will just learn some random words.
I'm kind of in the brute force category - just keep practicing till they are in rote memory. I would imagine that writing them down might help a bit too.
Everybody's different, but I just have to go over and over them. Even if I move on to the next lesson I'll still go back every day and practice the skill I'm stuck on until I'm happy that I know it well enough.
Would it help to make a list of the vocabulary? I do this as I go along and I have the definites, plurals, etc, side by side on a spreadsheet.
In those situations, I just keep moving forward. Duolingo will tell you when it is time to refresh your skill on past lessons. Some days I do not make any progress in the tree other than just strengthening the lessons that Duolingo tells me to.