It depends on the area and the store itself. Everyone wants something different, and the store is going to try and capitalize on that. For the most part right now the trend is printing in unique and original placement on the shirt, and allover prints as well. But there is still a solid market for a simple one sided centered print as well.
If you have a specific store in mind, you can survey the styles they are currently carrying. But the best thing would be to design what you WANT to sell, and find a store that suits that style. The market is large enough for plenty of variety!
