These are some oak cabinets I made for a coffee shop. They are made with 1/4" oak plywood for the sides and door panels and 1x2 oak for the rail on top, face frame, and door frames. The tops are Formica laminated MDF.
The doors were made by cutting a 1/4" grove down the edge of a long 1/2 and then cutting that piece to the correct sizes for the door frames (cut at 45 degree so they would meet up in the corners). The 1/4" Plywood was cut to fit inside the grove all the way around the door.
The Shelves above are oak 1x 6's and 1x2's.