A lighting scheme isn't that hard to design. Although there are an almost infinite number of light fixtures available on the market at the end of the day most light fixtures will do only one of two things: they either provide a background light or they provide spot or task lighting. So to develop your lighting scheme you simply need to combine these two different types of lights. But how do you know which you want and why?
Start by considering how people use the room. Is the room used mainly for reading or other activities that require good task lighting? Or is the room more often used by people using a computer or a watching TV. Usually the answer is a combination - which is why a mixture of both styles of lights are required.
Task lighting is more important in some rooms than others. You will notice that most kitchens include task lighting above the benches - without those lights the cook is usually working in their own shadow.
The lights above a bathroom's vanity are there for the same reason. In contrast if you need light for reading or craft work a floor lamp is often used as it can be positioned above and behind a person seated on a couch or chair. In an office task lighting is usually provided by desk lamps and similarly side-lamps work well in a bedroom for this purpose.Background or ambient light is less complex - the main trick here to position light fixtures so that they don't cause glare on computer or TV screens. Your style of decor will probably dictate whether you prefer fewer, but larger light fixtures or whether you prefer the modern down lights which require quite a number of lights to evenly light an entire room.
You should also consider how lighting can be changed to affect the mood of a room - dimmers are often used for this but also have lights on separate circuits means that you can light just one part of a larger space. Also, think about where you want your light switches too so that you easily turn lights on without having to walk into a dark area.
Designing a Lighting Scheme - Task Or Background Lighting?