Decide the desired size for the recessed shelving unit and the approximate placement on the wall. Avoid putting the unit directly above or below wall switches, outlets or lighting fixtures; this will make it easier to avoid the electrical wires in the wall. Find the location of the wall studs (normally 16 inches apart); the unit needs to go in between studs.
Use a straight edge and a razor knife to score the drywall. Use a hammer to knock a hole in the drywall inside the scored outline. Look behind the drywall to check for wiring and other obstacles.
Measure and cut the plywood for the shelving unit. For our project, we used plywood with pre-cut grooves for the sides of the unit to accommodate adjustable shelves. Plain 3/4" plywood was used for the top, bottom and back of the shelving unit.
Cut the grooved plywood so the grooves will line up when the piece is assembled. If the grooves are off, the shelves will be crooked.
Sand the shelving unit and trim, then either stain or prime and paint as desired.
The support behind the wall to hold up the shelving unit will depend on the weight of the unit and what you plan to display in the shelving unit. If the unit is heavy, attach 2x4s to the existing framing to add extra support in which you can nail the shelving unit onto. Line up the 2x4s to the edge of the drywall opening. If the unit is fairly light, slip strips of plywood behind the drywall, lined up with the edges of the hole. Secure these to the drywall with screws.
We purchased a sheet of acrylic which we were able to cut into six shelves. Home improvement stores can pre-cut the acrylic for you. Remove the protective plastic and slip the shelves into the grooves. Use double-sided tape to adhere small, battery-operated lights to the top of the unit to better show off your treasures.