In the early days of writers' lives, our works are our babies, and no one wants to be told that the baby is ugly, or has bad manners, or isn't the brightest tot on the block. It's hard sometimes even for a pro writer to remember that the work isn't really our baby, and we must learn to separate ourselves from our work.
The trick with writing and publishing is to remember that criticism is about the work, NOT ABOUT THE WRITER. Criticism, constructive or otherwise, also isn't about the dream of being a writer, it's just another part of the work of being a writer.
Learning writing craft is similar to what an athlete does to become good at his game. We start out with no skills but work until each necessary skill reaches a certain level of competence.
It requires practice, even more practice, sweat, pain, criticism, the pained self-knowledge that we are not perfect, and a realization that the dream of being published or being on the team doesn't magically happen. Then the cycle begins all over again as we grow as athletes or writers.
As a writer, you have a choice of whether you want to dream the dream or you want to buckle down to the hard work, the criticism, and the incredible learning curve of creating publishable craft.
The criticism, both positive and negative, will never go away if you choose to be a writer. You need only read the cruel Amazon reviews of some of the best writers to see that even fame, fortune, and success have an ugly side. Or listen to the stories from pro writers who have to deal with incompetent or control freaks editors and publishers.
The work of improving craft never goes away. It is the same whether you are a newbie without a clue or an established writer. Nora Roberts and Stephen King have said so, and I imagine any other writer you respect has said the same thing at one time or the other.
Dreaming the dream with no work or emotional toughness may be fine in the short term, but in the long term that dream attracts the predators-- the scam agents, fake contests, and vanity publishers-- who convince you that you are perfect then suck money and dreams right out of you until even the writing is no longer enough, and the dream becomes a nightmare.
If you love the writing and want to be published, you need to decide if it's a goal worth fighting for as well as a goal worth the time and distress of learning the craft and putting up with the shit. If it isn't, you need to find another goal worth the effort.
