Determine the size of the bottles you wish to store in your cabinet.
Figure out the dimensions of your liquor cabinet, based on how many bottles you wish to store and the height of those bottles.
Figure out how much wood you will need. At the very least, you will need two pieces that is width by height, two pieces that are width by depth, two pieces that are depth by height, one additional piece for each shelf, and additional wood for edging, support and legs.
Purchase wood at a lumberyard.
Purchase other supplies like paint or stain, hardware and nails or screws.
Measure and cut each piece of wood so that you have a top, bottom and back.
Measure and cut as many shelves are you want in your liquor cabinet.
Attach each shelf to the back of the liquor cabinet.
Attach sides, top, and bottom.
Cut an additional piece the same size as the back. This will serve as the door and you can either keep it as one piece or cut it in half.
Attach door or doors using hinges.
Attach legs to the base of the liquor cabinet
Attach edging to create a stop for the door or doors. You can use hardware to keep the doors latched.
Attach doorknobs.
Paint or stain the wood to match your personal preferences.