I planned to have a sort of 'floating head' and didn't want any of the model to be touching the edges of the frame. I didn't sharpen the image because I wanted to leave it relatively soft (as taken) because I think that suits the high key look. I used a small softbox for this photo but next time will use a larger light source (e.g. umbrealla) to get softer and less directional shadows. Pennant (see comments below) suggested moving the softbox closer, as this makes the light source larger because it's closer to the model.