Rejections are part of the deal. Everyone who discusses pro or semi-pro writing says this (and if they don’t, they’re selling something). If you submit, you’re going to get rejected, and it’s probably going to happen repeatedly. It happens 
for any number of reasons: the piece isn’t a good fit, it’s just not to the editor’s taste, it’s good but it’s competing with other pieces that are better, or–and this sucks but for a lot of the time and for a lot of people it’s unfortunately true–what you submitted just wasn’t as spectacular as you thought it was when you banged it out.
If you’re going to keep submitting, rejections are something that has to be prepared for and dealt with, as much as either of these things is possible. Everyone’s coping mechanisms are different, but here are the things that I find work best for me when I’m facing the classic “Thank you for your submission. Unfortunately, we have decided not to accept…” response.
1. Let yourself be upset. No one likes getting these things. What it amounts to is “sorry, you weren’t good enough for us” and that is never a nice thing to hear, no matter how gently phrased. And rejection slips tend to not be gently phrased. They’re usually not harsh, but with the sheer number of them that editors have to send out, they don’t have the time or the energy to be responsible for tender author feelings. It stings. That’s okay. Allow some time to let it sting. That said, don’t wallow in it. Allow some time, but be strict in the amount of time allowed. Once it’s up, let it go.
A Trick of Light 