Don’t get bogged down in detail if it doesn’t matter. Rather, focus on huge things that do.
If you’re needing to increase word count, don’t change verbs from past tense to past perfect (had gone, had ended). There’s a time and a place, but if past works just fine, your readers will notice and will be annoyed.
Don’t always tell. Take the time to paint the picture. If you don’t, it might seem like an afterthought.
Don’t always show, but show more than you tell.
Don’t give up just because people don’t like your work. Not everyone’s going to like it, but if you stop, then the people who will like it will never see it.
Don’t be too discouraged, and don’t stop believing in yourself. Some people are born to write. Some work hard to get where they need to be. Some… are just in denial, and may or may never come around.
Don’t fret over rejections. A friend of mine and I would click on a link showing how many rejections Steven King, JK Rowling, and many other famous writers received. Find a link giving that info and click it when you’re down. But don’t expect to become the next Stephen King. Expect to become the next YOU.
Don’t quit your day job if you have one. Writing is hard work, and sometimes it takes a while to succeed. But once you make it and can afford to quit, feel free—writing will become your new full-time job.
Don’t get jealous when the people around you land contracts left and right. Okay, get a little jealous, but be genuinely happy for them. When it’s your turn, you’ll want someone to bounce off the walls with you.
Don’t stop writing.
Don’t let two days go by where you don’t write (if it’s within your power, write as often as you can). But, know your limits and take a few days if you need to. Proofreading and editing count as writing.
Don’t query as soon as you’ve written a project. Edit, critique partners, edit, beta readers. In my case, edit, edit, edit, critique, edit, final read.
Don’t edit the book you JUST wrote. Let it sit at least a week or two.
Don’t make readers get personal with characters they’ll never see again. Not every character needs a dossier of traumatic or empowering life events. UNLESS this person’s scar is exposing something that’s pertinent to the plot. (Say, the government, at one point, used to brand people. A cashier can have the brand. But if an old friend did it in high school when they were drunk, then it’s useless information that’s taking up precious word count space.)
Don’t assume everyone’s going to like the book. Not everyone likes pistachios (blasphemy), not everyone likes cherries (blasphemy) and not everyone likes chocolate milk (double blasphemy). And that’s okay.
Don’t assume your writing doesn’t have to change. It might.
Don’t be the only one with eyes on it. Find people who will tell you the truth about your sample and listen to what they say.