Light is what makes the world visible. It casts thing bright or dim, sets shadows to one, side, and brightens up the dark. It is the tone against which we live our lives, the unseen backdrop that is always present. Originally, our only source of light was what came from the sky, the sun, moon, and stars. Eventually we tamed fire, and then electricity. Now when trying to light up our lives, we have a wide variety of options available, each of which can set a completely different tone for an environment.
As mentioned before, sky lights, and most noticeably the sun, are the most ancient ways of creating illumination. In a home these lights can be controlled by blocking, or opening up windows. This can be done with curtains, shades, and other features which will control the amount of illumination which can get in. Unfortunately, without knocking a hole in the wall, you cant really increase the amount of sunlight that will shine into a room, and even when the windows are strategically placed, this form of illumination will only last as long as its day time. Therefore, you will need to resort to other methods for illuminating the home.
Fire is the next oldest method for lighting. This is usually done in modern times, using candles. The candle is a very particular form of light, as its flame can flicker gently, casting a very soft, intimate glow across a room. This is great for creating calm, soothing spaces, that have a slight energy, but which tend to relax the mind and soul.
Lamps are of course the most familiar lighting source in modern times. Our control of electricity has led to a huge variety of bulbs and fixtures being developed, each with its own peculiar method for illuminating a space. You should experiment with the different lighting options available, and try to find one which suits your environments particular needs.