A measuring tape, pencil and paper

 

Decide what kind of curtain you would like 

 

Decide where the curtain rod will go;

          The norm is 150 mm/6 inches above the window frame.

          For a tall  deep window inside the frame.

 

Decide how much coverage you would like;

          Curtains nomaly extend about 50-80 mm/3-4 inches on each side

          And 50-80 mm/3-4 inches on the bottom. 

 

Measure the window/door from side to side and add the extended coverage you want for the width.

Measure the length from the top of the door/window to the desired bottom point and add the extended lenth on the top.  

 

Consider how much privacy you want or how much of the background you want to block out, this will determine the amount of beaded lengths you will need.