When hanging the strip of paper next to the door, butt it against its neighbour in the usual way, allowing the other edge to overlap the doorframe.
Make a diagonal cut in the waste towards the corner of the doorframe.
Brush the paper down against the side of the frame, make a crease with your scissors and cut off the waste.
Smooth down what's left of the strip above the door, then trim off the waste, leaving a 12mm (1/2in) overlap pasted to the top of the frame.
Continue with short strips over the door, hanging the next full strip down the other side of the doorframe. Crease and trim off the waste as before.