Prepare a rough draft. Make necessary amendments. Check that all extra sheets are properly cross referenced. Make a copy for your records. Be sure to follow any instructions on how the form is to be completed.
Black ink is better for photocopying.
Do not pad out, or cram in, your answers. Neatness should be your main watchword. Avoid adding sheets. Busy employers may become annoyed by unwanted information. This defeats the main purpose of application forms.