How to deal with rejection?

With optimism. Or, at least, this is my case.

I submit a fragment of my NaNoWriMo novel - that I didn't have too much time, if no time at all, to review and re-proof - to a selection process, and in three days time I receive a nice letter announcing me that I am out of the editorial program. 

First, I was expecting such an answer, because I know that there are hundreds of thousand of mistakes and clumsy expressions (to be modest). I have a lot of work ahead, but only at the beginning of the next year, when I will finish in a decent way the other two editorial projects I have currently in various stages of incompletitude. Second, this answer, though negative, was a sign of life that I did something for my writings: I sent it forward - expecting that somebody else than me read it - and I got a feed-back. It is better than keeping it in my e-file. Third, every occasion of sharing your writing to the others is welcomed - with the condition of always trying to offer high quality work. It is an exercise of style and out of this you are getting some new experience and new ideas.

So, if you want to listen my beginner's advice in the generous domain of rejections: keep going!