Harvesting Skills: There are many skills that effect the rate at which you gather materials from blocks such as stone, ores, dirt, sand, gravel, and logs. Higher skill levels will drop several of the desired block, and will increase the chance that you instantly break what you are digging or chopping.

[11] Excavator - Cobblestone instant-break
[12] Quarry Worker - Cobblestone quantity
[13] Ore Miner - Gold, Coal and Iron quantity
[14] Exotic Miner - Emerald, Lapis Lazuli, Diamond, and Redstone quantity
[17] Nether Miner - Quartz, Glowstone and Netherrack quantity.
[21] Sand Digger - Sand quantity and instant-break
[22] Gravel Digger - Gravel and Flint quantity and instant-break
[23] Dirt Digger - Dirt quantity and Dirt/Grass instant-break
[31] Lumberjack - Log quantity and instant-break

Farming Skills: Several skill handle how effective you are at farming wheat or gathering other plant materials. The Plowman skill also affects the durability of plows. Note that in DwarfCraft it is much harder to gather both seeds and wheat, so level 0 farmers will not be able to provide an endless supply of bread.

[4] Seed Gatherer - Plow durability and Seed Quantity from hoeing grass.
[5] Melon Farmer - Melon Slice Quantity from Melon Blocks.
[6] Fisher Man - Rod Durability and Quantity of Fish.
[41] Wheat Farmer - Quantity of Wheat and Seeds from reaping grown Crops
[42] Exotic Farmer - Cane(Reed), Cactus and Cocoa Beans Quantity
[43] Vegetable Farmer - Potato and Carrot Quantity.
[74] Florist - Flowers and Pumpkins Quantity
(Repeat) [91] Alchemist - Can sometimes make extra potions and nether wart quantity.
[80] Shearer - Quantity of Mushrooms when shearing Mooshrooms and quantity of Wool when shearing Sheep.

Crafting/Smelting Skills: The crafting skills affect how many of an item you craft when using the normal recipe at a crafting bench. Many crafting skills have additional effects. The Smelting skills affact how many extra items are dropped from furnaces when smelting items.

[7] Stone Shaper - Stone tools
[8] Smelter - When smelting gold/iron ore, extra ingots and stone can be dropped.
[9] Iron Forger - Iron tools
[10] Diamond Forger - Diamond tools
[15] Wood Carver - Wooden tools
[16] Gold Forger - Gold tools
[32] Wood Splitter - Planks and Sticks
[51] Mason - Cobblestone Tiles and Steps and Smooth Stone Tiles
[53] Wood Crafter - Ladders, Fences, Doors, and Wood Tiles and Steps
[61] Book Maker - Books
[62] Brick Maker - Brick Blocks
[63] Demolitionist - TNT and damage from explosions.
[65] Rail Worker - Rail sections
[66] Baker Man - Bread, Pumpkin Pie, Cookies, Cake, and Baked Potatoes
[67] Fletcher - Arrows
[68] Grillardin - When smelting raw meets, extra cooked meats can be dropped.
[86] Exotic Armour - Gold and Diamond armour
[88] Sign Maker - Signs
[89] Torch Maker - Torches
[91] Alchemist - Can sometimes make extra potions and nether wart quantity.

Damage Reduction Skills: In addition to Demolitionist reducing damage from explosions, there are skills that effect fire, falling, suffocation, and lava damage. There are also skills that affect the durability and crafting count of armor.

(Repeat) [63] Demolitionist - Damage from explosions
[64] Fire Starter - Damage from fire, durability of Flint and Tinder
[72] Climbing - Damage from falls, short fall forgiveness
[83] Scout - Leather armor durability, amount crafted, projectile damage reduction.
[84] Soldier - Iron armor durability, amount crafted

Combat Skills: The Swordsman, Axe Swinger and Bowman skills affect the damage you do with those weapons. The swordsman skill also has a durability effect.

[85] Archer - Arrow Damage and Enemy Feather/Arrow Drops
[87] Swordsman - Sword Damage and Durability
[101] Axe Swinger - Axe Damage

Hunting Skills: These skills allow a player to gather more resources for killing enemies with sword or bow. Note that this mod completely removes drops from creatures killed in any other way, to prevent "automated mob farming"

[76] Nether Hunter - Blaze, Magma Cube, Pig Zombie, Ghast
[81] Animal Hunter - Pig, Cow, Sheep, Chicken
[82] Monster Hunter - Creeper, Skeleton, Spider
(Repeat)[85] Archer - Zombie

Exploration Skills: These skills benefit activities related to exploring, travel, and adventure. The effects vary widely, but should result in more successful forays into the wilderness, and more valuable materials brought home.

[71] Sailor - Boat Travel Speed and Boat break results (sailor>15 allows recoverable boats)
[73] Survivalist - Health gained from uncooked pork, fish, and mushroom stew
[75] Dungeon Delver - Monster Spawners can drop Iron, Gold, Diamond, and Lapis blocks

Other Skills: See details -
[99] Noble - Dwarf Fortress nobles are useless. DwarfCraft nobles mine obsidian better, and it costs 100s of eggs to train. Any player that collects 100s of eggs and spends all day mining obsidian is just like a Dwarf Fortress noble.