I’ve never started a clothing line, so coming to me for advice on the nuts and bolts of everything would be, to be frank, risky. So instead of writing up some pointers for you that might not necessarily make any sense, I’m going to point you towards a few links, that may be of help.
How To Start A Clothing Line is a blog about
European literature in the early 19th century, well, if you can’t work out what that blog is about then I’m amazed you were able to get on the internet. It is written by Jon Kruse, the guy behind Mediocore Clothing, who happened to turn 25 yesterday (Happy Birthday Jon!), and features pretty much every aspect of starting your own line, from boring admin stuff to designing and printing tees, as well as marketing so that you can actually sell the tees after putting so much time and effort into them. There’s also interviews with other people in the industry.
Fuel For Design is an ebook by Gino from Color Overload. If you can get over the excited(!) marketing speak on the website, I have it on good authority that it’s worth the $37, I’m sure I read other reviews saying it was good, but I can’t remember where they are now, although Rude Retro questions whether Gino has the experience to write such a book.
The Art of Apparel. This blog is like a regular tee blog, but with more of a focus on the industry side of things, recently got caught up in major drama for posting an interview in which someone said what they thought.
Emptees. Sometimes you’ll get absolutely nailed by forum members that would rather make a joke than help you (they’re mostly harmless though), but if you want to know pretty much anything about the tee biz then the answer can be found here. Make sure you use the search function before asking a question though.
T-Shirt Forums. Like Emptees, except without the Lolcats.
That should probably get you started, if anyone can think of any more wonderful resources please let me know in the comments.
Update: I happened to come across a couple more resources you may find interesting/helpful:
47 Essential Resources for T-Shirt Designers at GoMediaZine
23 Great Apparel Related Design Articles at My Ink Blog [via... someone, I can't remember who, if you're a tee blogger that posted this please let me know and I'll link you up]