Just like any other small business marketing efforts, you need to determine who your targeted audience is or will be when you decide to design or create a promotional t-shirt.
The following tips are a few points you might want to consider before you get started.
1) Determine Your Target Audience and T-shirt Purpose. When deciding who your target audience is you will also want to determine where the t-shirt is going to be distributed, what the message is going to be and whether you are going to directly promote your logo or business in your t-shirt design. Also when it comes to calculating your costs you might want to determine how many t-shirts you want printed in your initial run. Most printers reduce the cost of the t-shirt based on how many t-shirts you want printed but you will need to evaluate or compare overall pricing between printers.