Put the painter's suit onto the intended wearer.
Tape the white duct tape to the suit close to the wearer's body in several spots for a closer fit. Leave it slightly baggy for an "air-pressurized" look.
Attach miscellaneous items to the suit. For example, put a tap light on the chest, attach a calculator to the forearm, run hoses down the arms and legs, and put a white-painted cardboard box on the back to create a backpack. If you use hot glue, remove the suit from the wearer first, as the heat from the glue could hurt them.
Remove the suit from the wearer. Paint the suit an even white with a latex or acrylic-based paint, as it will be able to better handle the strain of a person walking around in it. Allow the paint to completely dry.
Paint the boots and gloves white. Accessorize the gloves and boots with the colored duct tape or smaller tech type objects.
Add flag patches, mission patches, rank stripes or name tags to the suit. Create these with something as complex as a graphic design program or as simple as duct tape and a permanent marker.
Use anything from a cardboard box to a bike helmet to create a helmet. It must be big enough to cover the wearer's head completely. Cut a hole in the front to see out of.
Create a plastic visor in the helmet by cutting the top and bottom off of the 2-liter soda bottle, then cutting it lengthwise. Attach it to the inside of the helmet with hot glue or duct tape. Place a heavy object on the cut piece of soda bottle plastic to prevent it from rolling up while it sets.
Drill air holes into the helmet. Good airflow will also prevent fogging in the visor.
Add a neck ring between the suit and helmet to increase the authentic look of the suit. Using a ring of black rubber (a small bike tire, for instance) will allow you to achieve this effect.