What do you need to know about a topographic map in order to read it?

Firstly orientate the map, know which way is up. What is the scale, how far is a mile or Km on th map ? What do you need the map to tell you ? Do you need to know where you are on the map ? What can you see on the map that you recognise ? Do you know what the symbols on the map relate to on the ground ? Is there a coastline or a railway line or a major road or a church ? It all depends on what you need from the map.... to answer your question depends on that really.