It takes a bit of time, I had friends interested in my designs already so not including them it took about a week for my first "real" customer.
Your designs are the most important part of acquiring new purchases, then it's up to the quality to ensure repeat ones. Keep plugging and poking your target audience, you'll eventually get their attention. I believe it is about a .5-2% (realistically expect about 1%) average conversion rate for online customers, so you should be able to expect your first sale once you hit 100 unique visitors or so (of course this is just based on averages). Do you have a link where I could check your shirts out btw?
Your designs are the most important part of acquiring new purchases, then it's up to the quality to ensure repeat ones. Keep plugging and poking your target audience, you'll eventually get their attention. I believe it is about a .5-2% (realistically expect about 1%) average conversion rate for online customers, so you should be able to expect your first sale once you hit 100 unique visitors or so (of course this is just based on averages). Do you have a link where I could check your shirts out btw?