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.
Ambient lighting: This sort of lighting covers the general bathroom space. You could have a centrally fitted light - a chandelier, for example, if you want to opt for a special and creative effect - or several bright lights fitted all along the walls. If you are planning on installing recessed lights, be sure you install several recessed light fixtures or use recessed lights in combination with other styles of lights. Just a few recessed lights will not do the trick. Be sure you use glass lens over the recessed lights; plastic turns yellow with time.
Interior lighting may be able to cover every style of bathroom. You can choose to retain the austere look of your bathroom or jazz it up with the very best fixtures. You might want to try getting ceiling downlights and pairing them up with wall lights or track lights to add some character to your bathroom. Find bathroom accessories that you will love so you can definitely enjoy your alone time in the bathroom.
They allow light to be evenly reflected across your face removing any shadows that may deceive you or make it hard for you to groom yourself properly in a timely fashion. Recessed lights are best for the shower stalls and areas over bathtubs and toilets.