Floors should be spotlessly clean. Be sure to include a wastebasket. Use a throw-away liner for more sanitary clean up. Paper towels and paper cups are more sanitary for guests. Extra towels, soap, tissues and toilet paper should be easily accessible.
Safety is also critical in the bathroom.
A non-skid surface or mat in the tub or shower is also needed. Check the temperature of your hot water to assure that no one will be scalded. Make sure that there is ample hot water for all your guests needs. This can be a most irritating sound for a guest trying to get a good night's sleep. Another safety feature you may want to consider at some point is the use of GFI circuits in the bathroom to prevent shock.