The quickest solution is to simply add one essential item to the Boeing 737 current after takeoff checklist; and that is "Cabin Rate of Climb .....Check". If the outflow valve, bleed or pack switches are in an inappropriate positions, the cabin rate of climb will show aircraft rate of climb and thus alert the crew to a pressurisation problem. The relevant dial can be easily seen by both pilots whereas the pressurisation panel switches are not easily monitored from the left seat.