There are currently 19 trainable skills in Guilds of God. All skills level up by obtaining Experience.
There are a total of 10 combat skills:
Melee Focus - Determines your accuracy with melee weapons, and allows access to higher tiers melee weapons.
Melee Power - Determines your damage output when using melee weapons.
Melee Defense - Reduces damage received from enemies using melee.
Hitpoints - A passive combat skill, which determines the maximum health your character has.
There are a total of 9 gathering and creation skills:
Woodcutting - Allows you to cut down trees for their logs. Higher levels grant access to higher tier trees, and faster chop rates.
Mining - Allows you to mine ores and clay.
Fishing - Allows you to gather raw fish.
Cooking - Allows you to cook raw fish.
Smithing - Allows you to process the ores you mine to create armor and weapons.
Crafting - Allows you to create magic armor, and urns for use in Alchemy.
Fletching - Allows you to create bows and arrows for use in Ranged combat.
Firemaking - Allows you to create fires to use for cooking.
Alchemy - Allows you to create spells for use in magic training, including teleports.
Construction - Allows you to build on the lands of Guilds of Gods.