Growing up, I would never have called myself a writer; I’m dyslexic, not a good speller, limited vocabulary, and perfect grammar doesn’t come naturally to me. The only writing I did was that which was required. I received a lot of negative feedback from my parents and teachers. It was deserved. I tried to improve but writing was never going to be my thing. (Or so I thought at the time.) But! I had a very active imagination and I was very good at playing ‘pretend’. I spent a LOT of time in the alternate universe in my head.

Then, in college, I had an English literature professor whom I could finally think of as my “favorite teacher”. He convinced me that I had worth – potential – and that I could effectively communicate my thoughts. He provided a lot of positive feedback on what mattered; content.

Moral of the story, per my experiences so far:
When it comes to giving feedback, negative criticism (even if “constructive”) can discourage involvement in the activity. It rarely leads to improvement, because practice will cease.
Positive feedback encourages the activity, which leads to practice, which leads to improvement.
Fan the flames, don’t extinguish them. Ignite the desire to improve, and forge a love for the activity. Quench, don’t kill.

Fast-forward years later: I still spent a lot of time in ‘escapism’ activities, like video games, as a coping mechanism. Eventually I discovered “Role Play” online, through Yahoo chat rooms. Not to be confused with purely sexual role play, I prefer to call it ‘co-authoring a story’. What started as an escapism vehicle, resulted in a love for writing and story-telling. I received a steady dose of positive feedback. Behind the scenes my spelling was improving, and so was my confidence. (To avoid the embarrassment of misspelled words, I typed into an MS Word document and c/p’d it into the chat box.) I learned character development, story arch and progression, and how to build reader interest. I became the role-player that everyone wanted to write with. Then one day, I decided to go solo. I deleted all profiles and cut off all online contact.

I began a novel. *crickets chirping*

Gone was the constant ego stroking, the steady diet of feedback, the daily dose of encouragement. After several months, I was starving. Yes, I had made considerable progress, but if I was going to continue, I needed at least some of the ‘food’ that had sustained me during my years of role-play. I returned to the online world – but not to co-authoring. I found writing / writers sites and posted excerpts there. The competition was tough. The comments were tougher. The bar was raised. My diet had just gone from milk to meat.
Most comments were very positive. “Give me more!” they cried. Yep, I ate that up. So I kept posting, kept finding more sites to post to. (I seemed to be hungry for something that I still wasn’t getting.) Eventually, came a bitter pill. It went down hard. At first, I spit it back out. Then, I thought back on something I learned in a business class: listen to ALL feedback and advice; analyze (or research, if need be) its merit; decide to heed it or toss it. The instructor gave an example of when she ignored the comment of a crotchety old neighbor and it cost her dearly. This advice had served me well in life in general, so I applied it to the writing comment. The criticism had merit. The delivery lacked clarity and an example of what was wrong and what would be right, but that was for me to figure out if I was ever going to grow as a writer. I needed that raw comment to prove that I can’t live on fluff alone.

So my advice to those who are reading the works of a budding writer is:
A baby writer needs milk. Be gentle and encouraging, but honest. (I don’t personally feel this is the time to nit-pick over word choice and sentence structure. The only message you are sending is that you are a better writer than they are. It’s not about you.)
Concentrate on the good, not the bad. Point out continuity or clarity issues but don’t kill the progress. Ask for more. Keep them writing.
Let the editor serve up the meat.

And my advice to those who are writing a work is:
KEEP WRITING! No matter what, don’t give up. It takes as long as it takes.
Find a way to keep motivated. If you need feedback, hopefully, you find someone that can be supportive, someone that keeps you writing. But no one can live on fluff alone forever.
Remember that not all food tastes good, but it may still have nutritional value. Your ability to glean and apply that value will improve with practice. Expand your palate.
When you are ready, find an editor and be prepared for the meat. This is part of growing. Do not fear this step. Your writing style will remain intact.

Write, grow, repeat.