Choose your materials. If you want a lightweight wood, choose something like pine. It's a bit softer than. For cabinets that will go into a mobile home, using sturdy particle board may be your best bet. The length and depth of the sides and shelves will depend on the depth of your cabinets and how much space your kitchen has. Measure accordingly, remembering to also suit your personal tastes and storage needs.
Start by assembling a base composed of particle board, and cutting it to be the length of your cabinets and the depth of your counter. Mark the insides of the boards to be used for your cabinet's sides to show where the shelves will go.
Use a radial saw to cut dadoes onto the lines and then shift the stock slightly with each pass.
Assemble your cabinet by using wood glue or 6d nails. Attach the sides to your base, nailing at the bottom across the entire length of the side. Nail again all the way across where each shelf will go. Insert the shelves and glue into place.
Attach a cross brace by using glue and screws on the sides, and then again at the top
Install the cabinet's face by screwing hinges on the side from which it will open and then to the face. You can buy premade faces at home improvement stores, or you can make your own to fit your own specifications.
Hang the cabinet by drilling a hole through the cross brace and into the wall studs. Be sure you locate the studs ahead of time using your hammer and ear or a stud finder.