I am getting fairly well acquainted with Old Norse; I've developed a decent vocabulary and a taste for the vocabulary.

However, I am having two main problems:

First, how can I determine in which case the name is? For instance, when I saw Áki konungi, I thought - because they each have the same suffix - that they would go together. I was later told that I was not.
I've been reading þorsteins Saga Víkingssonar and came across Gauta Konungs. Konungs in genitive, which indicated possession; I am not sure which case Gauta is in. I do not wish to make the same mistake with Gauta konungs as I did with Áki konungi.

And second, how do I determine which translation to use? Some word, I've found, have a number of translations which could conceivably fit; however, those translations also have vastly different meanings.

Old Norse has been a very enjoyable language to study; it is a shame that there aren't many chivalric sagas online. I only browsed through (http://www.dur.ac.uk/medieval.www/sagaconf/matyushina.htm) and had developed a strong desire to read them.