Cartography
In order to really maximize your skill gain, you should take advantage of either a Skill Tutor Statuette or a Crystal Ball of Knowledge. It will help keep your training in the "Optimal" difficulty range.
0 - 20: Buy from a Mapmaker NPC.
20 - 58: Make Local Maps.
58 - 73: Make City Mpas.
73 - 83: Make Sea Charts.
83 - 99.5: Make Worlds Maps.
99.5 - 100: Take advantage of GGS gains and just decode a treasure map a day or three (depending on your total skill level) for the last .5 skill points.
0 - 20: Buy from a Mapmaker NPC.
20 - 58: Make Local Maps.
58 - 73: Make City Mpas.
73 - 83: Make Sea Charts.
83 - 99.5: Make Worlds Maps.
99.5 - 100: Take advantage of GGS gains and just decode a treasure map a day or three (depending on your total skill level) for the last .5 skill points.