How do you keep motivated to write after rejection?
Answer: It ain't easy. Rejection hurts. Self-doubt happens. Writing is personal; it's a part of you. To have a part of you rejected hurts. There's no getting around that. However, to keep going in this business (and yes, it is a business), you have to change that part of your thinking. Yes, what you write is a part of you, but you can't take that rejection personally.
What makes one agent/editor say "No, thank you" and another one email you and ask for a partial is PREFERENCE. Their personal preference. A rejection doesn't mean that your work is bad. It possibly means it could stand improvement. And that takes you examining your work with a critical eye. It helps to step back from it for a few weeks before sending out queries, then reading through it again. Does it still give you that same thrill? Or do you see places that aren't as strong as you thought they were? Looking at your book with fresh eyes can do wonders.
And adjusting your way of thinking (that rejection isn't personal) is vital to being able to push on through those rejections. And if you're like me, you'll get plenty of them before you hit pay dirt. If you're a writer, really a writer, you deal with it and you move on. Agents and editors WANT to find that golden needle in that haystack. They love great books, they love a compelling, page-turning story -- and they absolutely adore the writers who can give it to them.
I've heard it said many times, and I sincerely believe it's true: getting published is just as much about persistence as it is about talent. Plenty of talented writers got angry, got frustrated, got discouraged, and guess what? They didn't get published. They threw in the towel. As a result, no one got to read their books, to see how talented they were, because they gave up.
That being said, talent is a part of the equation. And nurturing talent takes practice, lots and lots of practice. For the vast majority of writers, success (i.e., reaching the goal of being published), takes a couple of manuscripts that are more than likely stuffed in a closet, before we write something publishable. (I've got my own "closet books.") Writing is hard work, but it's incredibly rewarding work.
I wanted to be published so badly that I was willing to write every day, even when I didn't want to, even when I didn't feel inspired, or even when I was just too danged tired. I wrote regardless of pretty much everything. That's not to say I didn't take the occassional day off. It's a good idea, for me and for my ever-patient & supportive husband Derek.
And a lot of people (sometimes family, friends, co-workers) don't take your work seriously. They think that if you haven't been published, that you're not a real writer. That's a load of bullpucky. If you write and work hard at it, you are a real writer regardless of whether you've ever signed your name to a publishing contract or not. And don't let anyone tell you otherwise; and if they do, don't believe them. I always told people that it wasn't a matter of IF I got published, but WHEN. Determination will take you a long way.
That's the biggest thing right there -- you absolutely must believe in yourself and what you are doing.
I've got a sticker on my computer that says "If they can do it, you know you can." It's been there for years, and I have no plans to take it down. Believe in yourself and your work -- if they can do it, you know you can.