If you have ever tried to cut or trim veneered pieces like a door, you know splintering can be a problem. A solution is to use a utility knife with a new blade and a straightedge to mark the cut line deeply on both sides. Some carpenters also use masking tape before making the knife cuts to stabilize the edge and protect wood from the saw making the final cut. Most important is to have a sharp fine-toothed blade in the saw.
Just about everyone knows to apply light penetrating oil or silicone spray to the hinges. But to really rid your door of squeaks, use your hammer and pry bar to lift the hinge pins up an inch or so. Apply the oil or spray to the top of the hinge, then wait a minute or two before you tap the pin back in place.