These are some of the best ways to sell t-shirts
Other way is to prebook them which means you sell them before you make them. Like Merch By Amazon worls, Make social media pages/accounts on FB, IG, Twitter, Pinterest, tumblr and other niche blog sites.
You should have a shirt design or a few and want to place them on templates (if you would like, use my product customizer.) After uploading and placing the design, you can download your mock up for free and then post it to your social media or personal website. Tell all of your followers what you are doing and give yourself a week or 2 to collect orders.
NOTE: You’ll need a good 12–24 shirts to be ordered if you only keep the print to one location (front) with 1–3 colors and sell them for $20-$25.
Once your money is collected by paypal, square, stripe or even cash, use that money to make the shirts and then ship them or hand them out to your customers/followers (add $3 to ship USPS in flat rate box or bag).
It mighf take a good 5–10 days to get them printed from your screenprint shop so tell your customers/followers that as well once you close the time to take orders.
If succesful and you are able to profit, repeat and repeat.
I recommend you to sell some new fashion and latest trending t-shirt is the best way to get good sales.