Shards always sell good, depending on the price. You might have a lot of business competition. Prices might vary alot. If you sell them to cheap, someone will just come and outprice you. But that might be even the case, if you sell them for the normal price on your server. All depends on your server economy. =)

Knowing what the Crafters on your Server need is also a good way to make money!

Like someone said above already, DoL classes are a heaven of nice money. But you need patience! DoL classes rank up extremly slow, it's alot of running around, and you must know whatyou do. Just running around and hitting trees and mining spots won't get you anywhere. So reading guides and consult databases is a must here!

I leveld all my fighting classes on Sheeps from R3 to at least R10. The Sheepskin are really good money, and the Sheeps even drop the always needed Wind Shard / Crystals.

High Level Leatherworkers need Skins/Hides for skilling up their class (Farming)
High Level Carpenter always need Log (Oak, Yew, Walnut, Willow) for skillups (Botanist)
High Level Weavers need alot of Flax for skilling (Farming, Botanist)
High Level Alchemists need alot of Fishes for skilling (Fisher)
High Level Blacksmith, Goldsmith and Armorer need tons of Ore for skilling (Miner)

Just check a Database for Recipes which only need a few materials. For example, the Halfmasks and Masks, a Carpenter is skilling on, only needs one Lumber. And out of one Log you get 4 Lumber. Alchemists just need one Fish and can turn it into Crystals. The metalworker classes need more then just one material per synthesis, but most of the time only one of a kind, like 4 Iron Ore, 6 Iron Sand, and so on and so on.

That's why you can make tons of money with just a single material. The good thing about DoL is, you don't need it extremly high to make your first money. For example, you can gather the first Iron Ore at Grade 3 spots. Which you can tackle around R18 miner. That's when you get the skill to sense nearby Grade 3 spots. At R18, it's still extremly hard to get Iron Ore out of a Mining Spot. But your rate will increase with your rank.

Just get to know your economy, what the people on your server need and what they're willing to pay. =)

I always suggest Shards and Sheepskin for people who only recently started the game and don't want to start a second class.