Unscrew the hinges and remove the doors from the cabinets. Remove the handles on the doors and set aside. Place the doors on a flat surface.
Fill a bucket with warm water. Add trisodium phosphate cleaner according to the package directions. Wash the cabinets and doors with the TSP solution using a sponge. Rinse them with clean water and dry them with a lint-free towel.
Apply a finish stripper to a soft cloth and wipe it onto the cabinets and doors. The stripper will vary with the type of finish on the maple cabinets. Paint stripper will work on a polyurethane or varnish finish. Lacquer thinner will strip a lacquer finish. Denatured alcohol will remove shellac.
Let the stripper sit on the cabinets and doors as long as directed on the label. Scrape off the softened finish with a putty knife.
Use a 150-grit hand sander to remove any remaining finish, sanding with the grain of the maple. Follow with a 220-grit sandpaper, sanding the entire cabinet and all the door surfaces. Wipe the dust off with a tack cloth.
Apply the gel stain to the maple cabinets with a foam paintbrush, following the grain of the wood and using even, overlapping strokes. Apply it to a 2-foot section, then immediately wipe the stain off with a lint-free cloth.
Continue applying the gel stain in 2-foot sections until you have done all of the cabinets and doors. Let the stain dry, then apply a second coat for a darker color. Let the cabinets dry 24 hours, then reattach the handles and hinges.