How to shoot a conversation and somebody walking

To shoot a conversation, similarly with shooting someone walking, you need a variety of shots in order to make it interesting for the audience.  You must always shoot in using the 180degree rule, this makes sure it does not confuse the audience and you are always shooting looking the same way. You can also include over the shoulder shots in order to show the person who is being talked to. 
cut-away shots are also often used cutting one from the person talking to the other, in order to see who is talking, when.

Shooting someone working often uses much of the same shots, however, there are a few more shots which can be included in order to make the cut interesting. You can take a shot of just their feet, for example, strangers on a train. This adds mystery, especially in thrillers, to the shot as the audience are unable to see who the person is and where they are going. You can also include an over the shoulder shot of the person who is walking, this gives the effect of someone being followed. You can also include a long shot showing where the person is walking to, which can also be called an establishing shot, giving the audience a sense of location.