Making window treatment decisions can be a daunting task. The official terminology of styles and how they attach to the rod seem to vary depending on who you talk to. If you're thinking about ordering drapes or making them yourself, this little primer will help steer you in the right direction.
Pencil Pleat: Pencil pleats are the most common simple pleating system using heading tape, enabling the curtain material to be easily gathered. Use it with tracks or rods, in bedrooms or living areas. It's suitable for all fabric types, and generally provides a simple, casual look and is usually inexpensive.
Pinched Pleat: (sometimes called 'French Pleating') Knife pleats pinched in groups of three (or sometimes just two, or even single), with spaces between which spread when the curtain is extended. It reaches full potential when used on track rods. Suitable for all fabric types, and its classic look makes it best suited for formal rooms of the house.
Eyelet-top Heading: Metal rings are punched into the heading using a special device, usually about six to eight eyelets per drop, making it normally a more expensive option. This type of curtain doesn't need as much fullness of fabric so it stacks back to a minimal space. The rod needs to be fitted well above the architrave.
For three other styles, check out the full post at Soft Furnishing New Zealand plus other valuable window treatment information.