Back in the Paleozoic era when I first considered writing a novel, I didn’t realize that (a) it could take a long time, (b) a publisher (or publishers as it turned out) might not care much for what I wrote and (c) it could take a long time. Nearly twenty years after I tried my hand at writing a novel, I was offered a publishing contract.
What did I learn along the way?

1. If you have a dream, stick to it, believe in it and be prepared to work – hard. Popular culture glorifies a five-second reward system: dream it, get it. But if you really want to keep it real, work for your dreams. Making a dream come true takes more perspiration than inspiration.
2. Don’t be afraid to revise, rework or throw the whole thing out. Every writer that I know makes the revision process a part of their life. Writing is a lot like sculpting – the sculptor takes a lump of clay and fondles it, shapes it, shaves some of it, forms it, forms it again and then starts over. Writing is work – joyous work for me – but still work. You have to rearrange the words until they say what you want them to say. Remember – you’re trying to make the reader feel something, see or smell something or react. “No tears in the writer, no tears in the reader.”
3. Rejection letters are a badge of honor for writers. I used to take the rejections personally and agonized over each one that I received. Eventually, I’d received so many of them (!) that I realized how subjective the process is. What you’re looking for is an editor who feels the same way about the project that you do. That can take some time. An example: fifteen years ago, an editor rejected a book of mine entitled somethingorother. I seethed for weeks. Ten years later, I got an enthusiastic phone call from that same editor about what would be my first book in print, Dancing on the Edge of the Roof. She couldn’t say enough good things about. And she went on to be a supportive and enthusiastic editor for my first two books at Ballantine. You just never know. As the late Olivia Goldsmith said, (and I’ll paraphrase) – It’s all about finding the right chair for the right behind.