One thing you no doubt know by now about T-shirt direct marketing is that it's extremely competitive. Finding an idea that stands out from the crowd isn't easy when so many others do the same thing. However, creativity has always been about borrowing from others and putting an artist's original spin on the idea.
Even the greatest artists in history did this, though it's impossible to become completely original in such a creative world. In the T-shirt industry, it's important to think with the same frame of mind.