There are several different types of curtains each with their own style and features. Although, most types of curtain can be used in most situations there are some that are better suited to certain situations than others. There are three features of curtains that can make a difference to their look and usage. The heading (or how the curtain is fixed to the pole), the curtain itself and the pole.
The heading of the curtain refers to the construction of the top of the curtain. The most popular curtain top is the pencil pleat. This is where the curtain is hung using a number of hooks and is pleated in way that when closed is said to look like a row of pencils. The second type of curtain heading is the tab top curtain where loops of material sit above the main shape of curtain that look like tabs. The third type of curtain heading is chrome ring or eyelet curtains where holes are cut through the top of the curtain and a (usually metal) eyelet edges the hole to make it robust.
As with all design there are no hard and fast rules but generally speaking pencil pleat curtains are used pretty much anywhere except bathroom, tab curtains are usually used in social areas such as living rooms as they do allow a little light into the room and chrome ring or eyelet curtains would be used in bathroom or rooms of more contemporary design.
The curtain pole used can also make a difference to both the look and practicality of the curtains. Certain fixing will only support certain headings. For example, eyelet curtains will only work with poles as opposed to rails. Therefore, when considering which pole to choose you first need to consider the curtain heading you desire. The second consideration is the usage of the curtain. When you wish to achieve a lighter room or let a little light in even when the curtains are closed then wooden or metal poles are probably a better bet than plastic rails. The shape of your window bay may also be a consideration with plastic rails being more flexible and versatile. Although in most cases solutions can be found to using the alternatives.
The curtains themselves can have a dramatic effect on the overall look of a room. Darker designs will make the room look darker or can have the effect of making the room feel more enclosed and therefore make you feel safer or more protected psychologically. Lighter designs will brighten the feel of the room and yet still maintain your privacy. The material used including its quality and weight can also have an effect as can whether the curtains are lined or not. Unlined curtains are lighter, easier to maintain and allow more air flow whilst lined curtains hang more naturally and provide better privacy and protection from the light.