A range of headings can be offered (see below photographs).  Curtains are lined with a quality cotton sateen lining which protects the curtains from the sun.  Alternatively you can choose a blackout lining which helps to block out the light and make the room darker. 

Curtains can be interlined to create warmth, fullness and a beautiful drape.  I recommend full length curtains be interlined in particular and I use a wonderfully soft cotton domette interlining.

French Double and Triple Pleat

For a more traditional look the left-hand photo is a double pleat to pattern curtain heading.  
on the right is a triple pleat headed curtain. 

Single and Cartridge Pleat

On the left is a single pleat headed curtain and on the right is a cartridge pleat headed curtain.  There is more fullness in the cartridge pleat and the tops are stuffed with interlining whereas the single pleat stacks back more minimally. 

Cottage Pleat

My client wanted a very informal, relaxed look for her bedroom.  Pooling the curtain bottoms added to the relaxed look.