My thoughts on the topic of learning to write is that it is the information and skill that matters, not the process in receiving it. And, ideally, we would gain information from academic resources and by hands-on training. I'm a bit of a study bug, I love doing courses on just about anything, but mostly writing. Here are some ways I think we can learn the craft:
Degrees in Literature/Writing. I've seen some writers poo-ha this method, saying that you can't learn to write by studying literature and you don't need a university degree to write. Of course you don't need one - but I learned a lot about the structure of novels and the various genres by studying. It's not for everyone, but it is rewarding.
Online Courses. I took on a course with Sydney Writers Centre, they have many great courses on creative writing, including Writing Books for Young Adults and Children. You get great feedback on your submissions and lots of online support.
Self-paced Courses. This takes some time-management skills. I've enjoyed Holly Lisle's How to Think Sideways as a way to learn while I write. The information is extensive and the activities are directly related to your work in progress. My favourite self-paced course though is Lisle's How to Review Your Novel - this is an amazing course that teaches you absolutely the BEST way to edit that first draft.
Writers Festivals. I went to my first last year. It was AMAZING. I picked up so much in the CYA Conference in just one day, I'll be back again this year. I'm hoping to attend a few more this year too (if I can get the time from work). If you need to know why you should attend these festivals, check out my post 8 Reasons to Attend Writers Festivals.
Books on Writing. There are so many available (and so many on my bookshelf), that I won't list them, but you can judge books by the star rating that Amazon provides and read the reviews to see if they are helpful (or search through my blog, I often list the ones I recommend). Choose books that address your weak points. If you are new to writing you might want to try some writing exercises, or maybe you need help with plotting, or dialogue. There's a book for every step of writing a novel.
Audiobooks. How have I gone so long in my life before discovering these? There are some great books that include writing exercises. Those ones seem to work best for audio. The text book information is hard to focus on for long periods, but some run like classes. The best thing about audiobooks is the time-saving, you can listen while in the car, walking the dog, washing the dishes, etc.
Blogs. There is an endless depth of knowledge being shared through blogs. I am amazed and warmed by how friendly and supportive the writing community is. Mostly we search through and blog information is disposable, but when you see something really helpful, bookmark it or print it off and file these in categories such as plotting, character, dialogue, editing... etc. So when you do need help in that area, the information is easy to find again. I create pages of links under those headings, so I can use them again and can share them with you. For example, here is my list of links for Novel Writing Structure.
Reading Fiction. Take notes while you read of any great examples of dialogue, metaphors, writing style, etc. Try to mimic your favourite passages, this is a great exercise in strengthening your own writing style. Make lists of what you think the author did well and what you would have done differently.
There are many more ways to learn writing such as finding a great mentor, receiving feedback, practicing, etc. You can check out a few more resources at 13 Best Resources for Writers.