Also don't build your reactors in locations prone to quakes and flooding, and if you do don't design it for the bare minimum safety requirements.

Also make sure that the staff is following procedure and not trying to keep the nuclear reactor going when important valves are closed, or mistakenly belief that a light indicates another important valve being open/closed instead of simply indicate if it's receiving power, as a result they didn't notice it was stuck open. (Three Mile Island)

On a tangent, The Onagawa Nuclear power plant located further north on the coast from Fukushima was actually close to the Quakes Epicentre but survived without major damage and all reactors shut down safely.

Why? Because back in the 60s one man on the design comity insisted on a seawall higher then minimally required (14.8 m above sea level instead of 12 m) and additional safety precautions to deal with the water line receding before a tsunami with the construction of a reservoir with enough capacity to cool the reactors long enough to shut down safely.