This is one of those obligatory posts that all writers must write to all other writers, for these are the big mistakes that other writers make, and they must be warned, by God. This might be useful advice, or it may just me stroking my own ego for a while. No matter the sucktitude, read on.
The biggest of all writing errors is not writing at all. Beginning writers often talk about how much they want to write, if only ... something. Yeah, something. The truth is, writing isn't anything other than an act of will. Writing is something that you choose, and only happens when you choose it over everything else that is more interesting and rewarding. The rewards of not writing are no words, no learning, and nothing to read. That is the worst literature out there, or possibly the best, depending on your point of view.
TWO - Revise
I've advised many beginning writers. My advice usually begins thus: Congratulations, you've written a first draft. In another 5-7 drafts, you'll have a good story. I do this because beginning writers have no idea what it takes to create a finished story. Some pro out there might be able to write a story in two drafts, and congratulations if you get there yourself, but to begin with, you need to revise.
Revising isn't editing. It's not tweaking. It's not adjusting. Revising is rethinking. Revising is tearing out something. Revising is violence. Revising is the necessity of admitting that you were wrong. Revising dares to do what you didn't dare the first time.
THREE - Feedback
Beginning writers focus on whether their writing is good. That's bad, and it's bad because good/bad is a dichotomy. Is your writing good or bad? That doesn't leave any wiggle room. Worse, it doesn't provide the writer any useful feedback.
When getting early feedback on your writing, focus on what grabs the reader and what loses the reader, because no matter what you write, some parts will be bad, tedious, or just not work, while other parts will work.
FOUR - Practice Book
Beginning writers begin by writing the story that they most want to tell. That's a problem. The first time that you do anything is usually terrible and you just threw your baby into terrible. Instead, you should start with a practice book. The point of a practice book is practice. Writing is a complicated art, and all the coordination surrounding a book just takes time to develop. You could go to many writing seminars, I suppose, but it's cheaper and more effective to just write a bad book.
Your first book teaches you about more than writing. That's where you develop your discipline, style, and voice. That's where you develop your self-criticism. That's where you do thing wrong and figure out how to salvage what you've done. That's where you learn what you do well and what you do badly. That's where you learn how to handle a book as a whole.
After your practice book, your next book will come along far easier. Your anxiety level will be lower. You'll have a better eye for what to do. You'll make choices that account for your strengths and weaknesses, and you'll make some new mistakes.
You always make mistakes.
FIVE - Professional Quality
I've seen too many self-published books where the author never compared his quality against that of professional publications. Even simple things like formatting and paragraph spacing were not compared.
If you want to write with the big boys, you need to be able to compete with them. To do that, you need to reasonably match the quality level of those works. If that sounds hard, it is, but it's not impossible. It just takes attention and commitment. All you really need to do is to compare your book to that of a an appropriate professional and see where your work fails.
Visually matching your work to professional work is among the simplest things that you can do.
Why do you match professional works? Because readers are used to it. A reader is far more likely to lose herself in your story if the formatting is familiar. When the formatting is idiosyncratic, then your formatting grabs her attention rather than your story. The formatting keeps ripping at her attention, which is not what you want.
SIX - Avoiding Mistakes
Beginning writers seek to avoid mistakes, or so most advice givers presume. Fuck that. What makes a professional is not somebody that avoided mistakes, but someone who made them. Making mistakes is never a mistake. Go make mistakes. Make them on purpose. Make them egregiously. Misspell every freaking word in a manuscript. Put the end in the middle and the beginning at the end. Just go and make those mistakes.
Mistakes aren't bad. Mistakes are not shames. Mistakes don't hurt you. If mistakes hurt you, then we'd have no writers left. No, do not fear them. Mistakes are badges of honor that we wear with pride. They are the dues that we pay to produce quality work. They are the lessons that school us. They are the pain that unites us.
SEVEN - No Editor
Editors are not proofreaders. Proofreaders are technicians who make sure that the agreed upon rules of the language are followed. Editors are coaches. These are the people who stand back, examine what you are doing, and help you to improve your performance, whether it be by suggesting alterations to your stories or by pointing out sentences that read poorly.
There's a saying: those who can't do teach. Well, that's bullshit. Nobody would learn anything that way. Teaching is its own skill. A good editor means that your final product is substantially better than you would otherwise produce and you'll learn good stuff while you're at it. So get an editor.
EIGHT - Writer Groups
Until you establish a voice and a vibe, a writer's group is not good for you.
Each of us is a little alchemical factory, producing magic by our own unique little magical processes. Establishing how to work with that takes dedicated work. Some things will work for you while others don't. I can't tell you which. You need to navigate how to make those things work. A writer's group won't teach you that.
What a writer's group will teach you is the current group think about writing. That can be handy, but that doesn't help you at all. The group will point you in all sorts of directions, usually away from errors and mistakes, and that, we now know, is suboptimal. With some work and dedication, you will figure out how to make some difficult facet of writing work, because we all do. Every writer that I know writes in ways that I would fail at. Not being especially good editors, they will warn you away from their difficulties and solve problems as they would solve them.
You are better off with an editor that you work well with.
And that's my short list but useful list.