Rejection - in this business, most of us experience it. Sure, you can just self-publish all your designs, but many of us have to diversify our income streams, and that often means looking for third-party work, whether that's with magazines, yarn companies, or writing books.
At first, the rejection would really get me down. I'd ask myself why in the world am I doing this to myself, why do I suck, etc. The negative self-talk was really bringing me down.
Then I changed my attitude.
Just because I got rejected from a magazine or whatever, doesn't mean that my idea is bad. It's just not the right fit, right now. Maybe they received two submissions that were similar and had to pick one. Maybe they are publishing something similar in an upcoming issue. Maybe it's just a matter of there was a lot of good stuff and you just missed the cut. There are tons of reasons for my submission not being accepted, and, most likely, I'll never find out why it was rejected. Which leads me to my next point.....
Resist the urge to start a dialog about why your design wasn't accepted. If you have an excellent working relationship with the company, you might be able to get away with asking for feedback, but most of the time, you're just going to get a canned letter of "we had lots of great designs and couldn't pick them all." It's better just to move on.
Once your design submission has been rejected, what do you do? Often times, I'll submit the same exact idea for the next submission call that comes along where it might be a good fit. Occasionally, I'll tweak things if I think I can do something to make it better, but a lot of times it's about just changing some of the text and sending it along to the next company. But be sure to wait until you get that acceptance or rejection email! You don't want to be in a situation where you submitted the same idea two different places and they both get accepted. One at a time for your awesome idea is the way to go!
Sometimes, I'll self-publish the design after it's been rejected. That's what happened with my Wallingford pattern. And, guess what? It ended up being better in the long run, I made way more money self-publishing this design than I would have from a third-party contract. It's still one of my best sellers today!