Here are some simple guidelines for measuring and cutting wallpaper:
 

1. Add 6 inches to height measurement of wall and cut first strip of wallpaper to that length.
    
2. Unroll the second strip, lay it next to the first and match the pattern across the two strips. If you've chosen a random pattern, you won't need to match strips, but for repeat patterns you'll need to allow extra length to ensure the strips match.
    
3. Roll up the strips loosely with the pattern side in.
    

Some people like to cut one or two strips ahead, others prefer to cut each piece as they go.