Learn from people currently doing the kind of work you want to do. Follow them online, read their interviews, and go to their talks/workshops when you can.
The Business of Being a Writer by 
Scratch by Often the most current market information about publications and publishers is to be found online. These websites have a variety of useful information, from URLs for individual publications to response times at publishers. Double check information you find using these resources, and note that the most authoritative information about a particular publication is typically found on its website, often in a "news" or "blog" section.
Writer's Market
Literary Market Place
Poet’s Market
Children's writer's & illustrator's market
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