Teaching dogs the basic commands are so important in a dogs life. If they really know the basics well at home then try to get them to display these behaviours with varying levels of environmental distractions. How well do they recall, sit, down, stay or give paw in the park?
Having these basic commands on a robust cue are a real help if you dog then develops a behaviour problem. This will give you the tools to be able to get them to listen to you at safe distances while wor