Need help making a decent profit.

[ChameleonMS]

Being from Gilgamesh, I have experience with a large population server MB. Typically, I make about 350K per day (I am casual player with 2 retainers) selling the following items:
Dragon Skin map 75-100K
20-25 Glamour Prisms 9-12K (there are several prisms which sell for only 2-5K and I complete avoid those markets).

Now, there are several other items I dabble in, such at the 2/3* stuff you are trying. But, I generally follow these rules.
If the sale frequency does meet the following conditions it is just not worth my time to make it.
2/3* Tool/equipment pieces, 2-3 per day.
DoW/DoM, Levelling Gear, 2 per day.
Glamour Prisms, 30+ per day.
Minions, 2-3 per day.
Furniture, I do not bother but I should.
Relic components, raid food and potions; I enter and leave these areas of the market repeatedly.
Another small but interesting source of income from the MB is low end Materia; typically grade 3 battle materias sell in bunches for near 1/2 than Vendor sale value. I buy it up and sell it to a vendor.