Here's a simplified, text-only version extracted from one of the full tutorials. The illustrated, full-length one can be found
here. This was my initial version of the process, which still works very well.
Base1) Obtain the following materials: aluminum foil, duct and/or masking tape, a permanent marker, scissors, a knife, and a hole punch.
2) Layer several sheets of aluminum foil and fold them to a thickness at which they are no longer flimsy.
3) Mold the foil over the face, paying careful attention to depressions and raised areas such as the nose and eyes.
4) Take it off and sketch out the outline and eyeholes with a permanent marker. Be careful about the placement of the eyeholes, because they will be difficult to fix later.
5) Trim around the edges with scissors and hole-punch both corners for ties. Cutting out the eyeholes, however, is easier with a knife. Folding the foil in half may be necessary for symmetry.
6) Periodically press the foil back onto the face, especially after it has been worked with, to ensure that it retains its shape.
7) Tape, tie, or have someone hold the mask to the face. Begin covering the foil with strips of duct tape, using larger pieces for open areas and smaller ones for edges and curves around holes. The thicker the layers, the better the shape will hold.
8) The edges can be secured with masking tape, but this is not necessary. Any changes to the basic shape of the mask can be added with tape. When finished, lay the form aside and proceed to prepare the ingredients for the paper mache.
Finishing1) For the paper mache, gather these additional materials: newspaper, a water-soluble glue like white glue, and some water.
2) In a container wide enough for at least a hand to fit through, mix the glue solution. Blend two parts glue and one part water. The consistency should be runny but not watery.
3) Shred newspaper by hand, tearing it into small strips and bits. Smaller pieces allow for more control over edges and therefore a smoother finished surface.
4) Dampen the paper in the glue solution and plaster it onto the mask base. Squeeze out excess glue from underneath, coat the top surface, and smooth rough edges. Apply the glue with a flat stick, a paintbrush, or merely fingers. Use as many layers as seems necessary, and allow one side to dry before working on the other.
5) Decorative surface treatments can now be added to the mask. If paint is used, it should be protected with sealant.
Be warned, however! Watch out for what sort of tape you use for the base. Thicker, sturdier tape will hold up much better than its flimsier counterpart, which will refuse to remain rigid even when covered with layers of paper mache.