This New Shin Megami Tensei IV: Apocalypse Runs Down The Basics
Basically, don't let demons devour you. That's the gist of it.
Shin Megami Tensei IV: Apocalypse is the next entry in the MegaTen franchise that's coming soon, and Atlus has seen fit to release an additional trailer ahead of release that focuses on special techniques that can be used when fighting off the demons that'll plague you when you're exploring dungeons.
The advice is basically par for the course, including the suggestion to strike first when you're able to, exploit demon weaknesses so you can maximize damage, cast buffs and take note of how you can best keep your party from taking addition damage by casting them and using them where available, choose the best partners available to you based on the skills you need, and "don't panic." Well, duh. That's basically a given, right?
Shin Megami Tensei IV: Apocalypse is hurtling toward a release for 3DS in North America on September 20. If you start now, you can get into the original Shin Megami Tensei IV and see if you can finish it before time to dig into the next installment. It's definitely worth doing, so if you've got a copy you should try it out.