Like most of the money making guides, you'll have to wait to earn money. But with this, you should be able to make 2-3m each hour on average.
It sounds weird but it still works for me...

1. Make a new character.

2. (Optional) Find the npc shop called [Shield2] and buy a long sword from it.

3. Move to an area where there are level 1 and 2 monsters called "Aibatts".

4. Kill Small, Normal and Captain Aibatts and pick up EVERY "Twinkle Stone"(Quest item from Aibatts) you find.

5. When you get to level 2, press "H" and add your spare stat points on strength to kill them faster. Keep killing Aibatts until you are level 4. Add your stat points again onto strength again.

6. The closer your level is to a monster, the more drops you'll get so from now on, ONLY kill small Aibatts and normal Aibatts so you won't level up anymore.

7. (Optional) Search for someone shouting for party fillers and join the party. There will be a chance that the party leader WILL use the party skill "Gift Box" or "Fortunate Drop" and these increase the drop rates of monsters which means twinkle stone drop rates become A LOT higher. The only problem is that it's really hard to find a party that actually uses gift box or fortunate drop.

8. Once you are satisfied with gathering twinkle stones, go back to the town you started in (Flarine). Open a shop where people can actually SEE it and place the prices at about 30k-50k. RICH people will often come along wanting twinkle stones to speed up their new character's 1st job change so it does't take very long to sell.

9. There is 1 important thing to check before you open a shop. Look around Flarine first and see if anyone is selling twinkle stones. If they're cheaper, buy them if you have the money. If they're just slightly cheaper, make yours either the same price or lower. If they're higher, ignore them. If there are COMPLETELY NO twinkle stones in town, raise your price. (Don't go overboard like some poeple that price theirs at 100k)

10. AFK. Twinkle stones priced at 30k should sell at the rate of approximately 10 every 10 minutes. Although if they're priced at 50k... about 10 every hour or so. (Prices affect the selling speed a lot).

Note: This is in the Mia server so i'm not sure about how much twinkle stones sell for in other servers so prices and selling speed may vary.