Watching the capitalists
The first thing to remember about North Korea is that their main priority is regime continuation. Their leaders live like kings and they do not want to give that up. And they know starting a war guarantees the death of their regime.
So they talk tough to build up their young leaders credentials with the military. You must remember that in Korea age and seniority are very important. So a 20something leader is going to have considerably less prestige and respect from the military than his much older father did. To build up that respect, he has to talk tough and he has to act tough to win the military over. And the only way Kim Jong-Un will keep power in North Korea is with the military's blessing.
So they'll bluster and threaten to reduce Seoul to "a sea of fire". And they'll threaten to nuke New York (even though they can't even come close to doing it). And they'll tell foreigners to "get out of Korea so you will not be killed in a war." A few weeks ago they declared that they are now at war with South Korea (technically it's been in that state for the last 60+ years). And though all of that talk is bluster, there is a tiny bit of substance behind it.
After the bluster (when SK has dropped it's guard somewhat) they'll probably execute a small, very localized attack somewhere to prove how tough they are. Perhaps like last time, they'll shell a small island with SK troops on it for a short time. Or maybe they'll sink a ship like in 2010. But they won't risk open war with SK and the US because they are guaranteed to lose. And they know it.
Literally the only danger is one of escalation. If the North executes one of their small provocations and the South strikes back hard (which they will this time), then the North might be tempted to respond with a stronger retaliation which could escalate into a resumption of actual war. This is the worst case scenario. They won't launch an all out first strike because of the desire to preserve their regime.
The good news is that the above is a worst case scenario and is easily avoided many different ways. Though the North has "warned" foreigners to leave Korea, until the US or British embassies tell us to do the same we're staying here. Right now the threat is all talk. And both logic and all available information suggest that while the North seems crazy, they are very sane when it comes to keeping their own power. And starting a war with South Korea is the one sure way to lose that power.
And if things do somehow go bad, we'll all be getting out as fast a possible. The US embassy knows we're here and they will send planes to get us out if needed. So relax everyone not living in South Korea. Your friends and loved ones here are fine.
The DMZ border with South Korean troops guarding it during my visit in 2011