One of the least efficient cabinets in most kitchens is the one beneath the sink. Because the plumbing connections for the sink are made here, most cabinet makers leave the space wide open with no shelves or drawers. But you can make the most of this space by simply adding a removable shelf. Build a simple shelf from one by eight or one by ten pine. First, cut a long horizontal piece, slightly shorter than the width of the cabinet. Then cut two vertical legs to attach to either end. Now, slide the shelf into the cabinet and make a mark on it where it butts up against the pea trap and/or the drainpipe. Finally, use a jigsaw to notch the shelf so it fits around the plumbing. By adding another level to this cabinet you’ve effectively doubled it’s storage capacity.