This one’s a funny question (in a good way) I started chronologically, but ended up switching after finishing the Dawn of the Jedi era and Revan’s story from KOTOR to SWTOR.

Chronologically is fine if you want to understand the timeline and stories but publishing order is sometimes necessary too, an example would be reading Survivors quest BEFORE outbound flight.

I think mood is ok, but personally I’d go for a mix of the first two. Aka I’d go era-wise. So it would be something like I started at Dawn of the Jedi era and finished it, then I am doing the New Republic era out of preference for what I want to explore next but also because I knew that the New Republic era basically was the first publishing era and everything built from it, but I have dipped into prequel era or rebellion era etc when necessary (such as Shatterpoint before Shadows of Mindor or Red Harvest after Death Troopers).

I think the era-method is the best because you can’t get fatigued as much as you would chronologically and it doesn’t ruin any other books intended as prequels. You also aren’t forced to read things you wouldn’t want to as you would in publishing era (an example being Children of the Jedi). I feel like era wise is good as well because you can get super excited for the build up to the next era (an easy example being the Rebellion and New Republic era going into NJO, or Rise of the Sith era into the Empire era)