Drill holes into the bed's frame for wheels. Add large, decorative wooden wheels to each corner of the bed.
Build a headboard. Cut wooden boards or plywood to the desired size. Use a jigsaw to make a rounded edge for the top.
Embellish the headboard. Paint it white or black to match the look of a carriage. Spray glitter on the headboard if desired. Another option is to cover the headboard with red velvet fabric. Sew buttons to the headboard to give it the look of a tufted carriage seat back.
Screw the headboard into the wall behind the bed, making sure to attach it to wall studs. Add a small set of stairs near the bed. Construct the stairs with 2-by-4s, a hammer and nails.
Paint the bed. Use the same color as you used for the headboard if you prefer, or paint the frame and the stairs white or black.
Hang a canopy from the ceiling. You can pick up a pre-made canopy in the kid's section or the drapery aisle of a home store. Make your own by gluing fabric around an embroidery hoop and stringing ribbon from the hoop to a hook in the ceiling. Surround the sides of the bed with the fabric that cascades down.
Make the bed. Use fabrics that match the color of the bed, or that look like fabric that could be used for a seat inside a carriage.
Get an image of one side of a carriage. Use a transparency or an image from a computer and print on a standard piece of paper. This will provide the inspiration and the outline for the carriage design.
Project this image onto a wall with the use of an overhead projector. Adjust the focus and location of the projector until your image fits the scale for the carriage. Place a large piece of plywood in front of the wall. Use a marker to draw the outline of the carriage.
Use a jigsaw to cut out the carriage shape. Cut out a large section that looks like a doorway so the bed's owner can step inside the bed. Use sandpaper to sand the edges.
Prime one section of the carriage design at a time. Let the primer dry. Paint the section in the color of your choice. Let it dry. Repeat the process, working on one section at a time.
Use a second piece of plywood to form the other side of the carriage bed. Draw the outline of the carriage, cut it out, prime it and paint it.
Drill pilot holes into the side of the bed's frame where you plan to position the plywood pieces. Bolt the plywood sides in place with the use of bolts and nuts.