Sorry for the long time with no updates – I actually picked kind of a bad time to start this website and I’ve been busy with things so I forced myself to make an update this morning.
I posted a page describing Icelandic genitives, along with instructions for the two most commonly encountered problems for English-speakers: using the word ásatrúar, and making a Norse-y patronymic/matronymic-style name. I include instructions on using Beygingarlýsing íslensks nútímamáls to look up different forms of words including genitives, with lots of pictures and a few tricks for when you don’t quite know what to search for.
The post can be found here: https://ordstirr.wordpress.com/language/the-genitive-case/
I also rearranged the links at the top of the page so that they make some kind of sense, now that there’s a little bit of actual content on the site.