Measure the bathroom floor space and wall areas.
Sketch the room's measurements onto graph paper, including door openings and windows. Identify where you can add light and space, if needed. Consider enlarging a window or adding a section of glass blocks, for example. Add a 4-by-4-foot skylight in the ceiling of an extremely small bathroom to add a roomier feeling.
Identify the main fixtures that you require. Leave the toilet in its present location on the design grid, if possible, but upgrade it to a more contemporary design with water-saving features. Choose a shower in a pre-made unit design or plan a tiled shower with glass doors. Select a bathtub or jetted tub that harmonizes with the shower in every respect; for example, pair a cream-colored bathtub with a sand-colored tile shower. Invest in nickel or bronze faucets over inexpensive stainless choices.
Purchase the fixtures, cabinetry and sinks, and find a place to store them onsite while the old bath is gutted. Schedule exact delivery times if there is no storage.
Disconnect plumbing and electricity in the bath area.
Tear out old walls, flooring and old plumbing as needed, and haul old materials off of the premises.
Make any structural changes to the room as needed, starting with the ceiling. Add a skylight or recessed lighting fixtures, for example, or install a larger window in one of the exterior walls.
Install drywall and sub-flooring. Be sure to route all new wiring and plumbing through wall stud areas before nailing on the drywall. Install all drain lines and water lines in the floor joist area before nailing new sub-flooring in place.
Add a new new shower and bathtub, if desired, as well as faucets and accompanying hardware.
Finish the flooring. For example, lay vinyl sheeting flooring or install vinyl or porcelain ceramic tiles. Allow all grout areas to dry for 24 hours.
Seat the new toilet with a wax seal and attach the water lines.
Install the vanity cabinet and sink(s) as the room’s focal points. Keep in mind that the cabinetry's color or surrounding decor, including art or wallpaper, should draw the eye to the vanity wall.
Add lighting to the wall above the vanity. Consider a lighting bar with clear bulbs or an ornate light fixture that is secured to the wall above the sink space. Install a light fixture in the ceiling space, if you desire.
Add details to the room, such as shelving and towel bars, and install all baseboard materials throughout the space.
Secure a large mirror on the wall over the vanity.
Hook up the room's electricity once you’ve installed light fixtures and new electrical outlets.