First and foremost do not attempt to do any electrical work unless you have had the proper training. Hire a licensed electrician who has had the proper training and is up to date with local codes. Something seemingly simple like replacing an old receptacle can result in serious injury or disaster.
Remember, without light there is no color, form, or texture - period. Lighting can add depth and/or visual excitement to a bathroom.
If you have any receptacles in your home in which you plug something in and the plug droops out, have them replaced. These provide a poor electrical contact which will develop heat.
Be sure to have working smoke detectors in the required locations. Codes today require one in each bedroom, one in the hall adjacent to the bedrooms and on each floor of the living space. You should also consider having one smoke and Carbon Monoxide detector installed in the basement as well.
Ceiling fans can greatly reduce the strain on heating and cooling systems saving energy and cost.
Use ceiling fan bulbs in fans. They are made to hold up against vibration and last longer.
Never exceed manufacturer rated wattage for light bulbs in a fixture. If you see no label don't exceed 60 watts.
Always look for a UL label on all electrical appliances. In recent years I have noticed products coming from overseas or Canada that are not UL listed.