Follow Martha's easy, efficient system for making a bed perfectly.
Martha Stewart Living, Volume 15 August/September 1993
Begin with a good-quality mattress and box spring. Protect the mattress with a cotton cover; Martha adds a wool pad.
Unless you're using a fitted sheet, make hospital corners with the bottom sheet, starting at the bed's head: Drape the sheet evenly over the bed, leaving about 1 foot of fabric hanging beyond the head. Stand beside the bed, toward its center, and pick up a side hem. Pull the hem toward you into a taut crease, then raise the creased section over the mattress so the sheet makes a triangular tent over the bed. With your other hand, smooth the sheet flat along the mattress's side. Then fold the creased section down over the side, and tuck the sheet snugly under the mattress. Repeat the process at the foot and other side of the bed.
Add the top sheet, and make hospital corners at the bed's foot.
Leave the sides untucked for easier sleeping. Finish with a blanket, quilt, or down comforter.