Window Blinds come in many different styles and can be made from many different types of material. Typically, blinds are made with slats (vanes) made of metal, wood, Vinyl or fabric. Blinds are adjusted by rotating the slats from open position to closed position where they overlap, shutting out all light. Some blinds work from a single piece of material instead of slats.
Horizontal Blinds are ideal for windows that are taller then they are wide. You can choose horizontal blinds that are made from premium hardwoods, versatile aluminum, or durable polymers
Vertical Blinds are some of the most popular types of blinds on the market today. They are well suited for windows which are wider than than they are tall and slide from side to side .They are the ideal solution to cover large windows or glass (patio) doors. They provide both light control and privacy and can be easily motorized. The 2 main mechanisms in the operation of vertical blinds are sliding and turning. They can be easily slid to the side for full light (or, controlled remotely, if you wish)
For more details check out this link on Venetian Blinds