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.
Light Placement: Ahead of setting up the light fixtures, look at the sort of ambiance you intend to create with your bathroom. Mistakenly placed illumination can cause very unlucky and even terrifying effects that will very likely - if you're the very sensitive sort - have you scurrying out as soon as possible. It really is far better in case you give the illumination arrangements some thought and, with the aid of tactically positioned lighting fixtures, produce a enjoyable, peaceful and well-lit atmosphere that offers much incentive to linger in the bath.
Also the light can be reflected by using mirrors if they are placed in strategic places and you can get better results when decorating the bathroom. It may also be supplemented by a lamp or lamps perched on the bathroom cabinet if the electrical system allows this. All these will help you to have a stronger light when needed, but also a dimmer light to create a romantic atmosphere.
Accent lighting: Accent lighting, as the name suggests, draws attention to a certain area or feature of the bathroom. You can use it to good effect to highlight things like an ornate mirror or an artwork or a decorative wash-basin or beautiful tiling.