What should a pilot do to perform a successful emergency water landing?
What should a pilot do?


Follow the checklist?


  Is there any checklist?


There are many such checklists in the intertubes and whole books have been written on the subject



Here's the start of one for 737s



For comparison, here's one for a Cessna light aircraft




  Are commercial jets buoyant?


Yes, initially, if substantially in once piece. We know that because several intrepid pilots have tested this idea (obligatory hat-tip to Sullenberger).

It makes sense that the fuel tanks in the wings, especially once emptied of fuel, are buoyant. The wings are obviously capable of supporting the fuselage. The fuselage is a pressurised tube and should be buoyant too, until the passengers and crew start making large holes in it.