JOSM tutorial for an overpass intersectionhttp://russnelson.com/osm/2009-06-03_2227.mp4
JOSM tutorial for merging two parts of one road
http://russnelson.com/osm/JOSM-merging-ways.mp4
JOSM tutorial: how to save and then reload your work
http://russnelson.com/osm/JOSM-save-and-reload.mp4