In my experience, there are three main shop strategies. Each have their own advantages and disadvantages. I would suggest taking one of them and modifying it to suit your needs. You can even have a sort of hybrid shop, which is a stategy I reccomend and utilise to get the best of both worlds.
The first strategy is the worst one in my opinion. It's called overpricing. You sell a various things at higher than the average price (i.e. codestones at 10-15K, Faeries at 15K.) It takes forever to sell something using this method, but you do make more money everytime you sell something.
The second method is the most expensive one. It involves a very large shop (size 20+). Generally you sell things at average prices, some high, some low. You have a set price for everything. You build regular costumers, and your business is based on the trust of those customers. These types of shops rarely sell out. This strategy works well, but I prefer to mix this strategy with our next.
Our next strategy involves a small shop. You sell every thing for the lowest price on the wizard. Therefore your items go fast, and this is both a good thing, and a bad thing. You don't get regular customers because your shop is usually sold out. Also, you don't make as much money selling everything cheap. I would reccomend having a medium sized shop that sells things slightly lower than the shop wiz price, but not that much lower. that way you get the best of both worlds:)
The BIG shop
The CHEAPO shop
