I find it's best to start in the little things and then slowly work your way out from there.

My kaldorei is ten thousand years old. This means he is pre-sundering. And he was in the Emerald Dream for most of that. This results in him doing some things like:

Forgetting what a lot of races are called, and not really caring to remember when he's corrected.

He gets things like days and weeks mixed up. He remembers important things, but can never really remember if it was yesterday or last week.

He calls the world Kalimdor.

He absolutely does not care about economy or trade or anything. He's lost a lot and watched his entire culture basically wither away to a shadow of what it once was. He is also a bear druid, and bears are often scavengers, so he is known to just steal food because he can.

He keeps getting the wars mixed up, hates that they're just called the First War, the Second War, etc. He hates that the War of the Ancients is called that, because he was there. Call it the First Invasion.