I own a window cleaning company and have been running in for the last 15 years. That has kept me in close contact with hundreds of retail stores, many of which sell t-shirts. I decided to get into vinyl lettering of storefronts as an add on, so I bought a plotter and the software and began producing simple signs. That led to small graphics and vinyl stickers of "sayings" for peoples cars and such. Then I learned that I could cut Thermoflex for t-shirts with the equipment I already had. Then I realized that my brother bought me an Epson R300 printer for Christmas last year that I never put to use. Everything is falling into place.
Wait, that wasn't your question. Other than trying to learn about t-shirts, I sail boats, play guitar, ride the motorcycle, work on my snowmobile club's website, go to bars, take out the pontoon boat, fish, ski, work on my house, watch movies. Man, I don't have time to sell t-shirts.