Perhaps people should read the rather comprehensive "SMOKE, FIRE AND FUMES IN TRANSPORT AIRCRAFT" report by the RAeS and GAPAN.
PDF
here . Full of useful information.
(quite a large PDF by the way)
As for opening windows and hatches...
In cases of continuous smoke, no manufacture suggests opening a window, because it can cause the fire to spread. Several serious in-flight fires show that the flight crews opened the window without improving the visibility significantly and, in some cases it was made worse. An open window creates high wind noise, which prevents effective communication between crewmembers. The high noise level prevents checklist accomplishment and also prevents a crewmember from assisting the flying pilot during the landing with callouts (which may be vital in limited visibility of a smoke filled flight deck).