There is no rule such that the bathroom lighting should be provided only in the ceiling or is better if it is provided at the sides or on top of the mirror. One has to fix the bathroom lightings according to one's taste and the mood that he or she wants to bring into the room. Even for a small bathroom, people, these days, go for two or more lighting fixtures. Thus, lighting is the most important factor to be considered in any modern bathrooms.
Try accent lighting for illuminating your bathroom as it accentuates the lighting in your bathroom. This lighting option is not a necessity, but can be used for creating a decorative and dramatic look for your bathroom.
But the second aspect to consider when choosing your bathroom lights is safety. Clearly a bathroom is a wet area, and electricity and water are not the best of companions. Today however there's a very easy system in use which helps you to quickly and easily identify the type of light that's suitable for each area of your bathroom.
Natural light: In the event the style of your bathroom lets in a great deal of natural light, you should have only take into consideration illumination arrangements for after-dark hours. In other instances, you could have to use a mixture of natural and man-made light sources, or, even wholly man made sources to light up your bathroom. You can get a number of in halogen and standard incandescent lights available in the market. Choose the ones that are superb and bright and as close as possible to natural sunlight.