Look up the area in "Pokemon" that you'd like to make a map of. Lightly sketch out the basic area, labeling important places within the area. Everything in this stage should be lightly sketched and written.
Draw over your lightly drawn map with an ink pen or marker. Lightly pencil in the characteristics of the location such as where to find certain creatures or treasures.
Color in with colored pencils or colored markers. You can even scan in the map drawing and put it into a photo manipulation program to digitally color in your map.