Have well written original content of value. That's it.
Also helps to NOT listen to most SEO "experts" with their lies, bunk and other outright scam artist BS, as said bull is guaranteed to get you slapped down by the engines sooner or later.
Semantic markup, organic backlinks from people who care about your content, and social promotion can all help too.
Also helps to not have bloated/pointless code -- like TITLE attributes who's content is identical to the content of the tag it's being applied to... broken/gibberish heading orders making the document structure gibberish, pointlessly overstuffed keywords META...
But REALLY, this update is more about content. Really the only people for whom the Panda 4 update could be considered an "attack" are the SEO snake oil doctors and the people who were duped into thinking their fairy-tale bull has anything to do with reality.
Naturally that's why over the coming weeks as with every other previous update you'll see a bunch of ad-hominem attacks against Matt Cutts. Gee SEO scam artists trying to discredit the person who's job it is to smack them across the face with a wet trout -- shocking.
See the average SEO-tard's reaction to "write for the user, not the engine".