I may have posted about this before—after posting here for more than five years(!), it's hard to remember everything—but if I have, it's well worth repeating.
Agent Janet Reid's blog is one of top ten favorite writer's resources. She dishes out fabulous and free advice to writers at all stages of the publishing process. Recent topics include everything from general query advice, what to do when your agent quits and the other agents at the agency don't want to represent you, crowdfunding your novel, and ghostwriting. She is opinionated and funny, and her genuine care for writers shows through in every post.
The blog also hosts periodic short writing contests. These are a lot of fun and can be a great way to hone your short-form writing skills or just improve your ability to say a lot without using many words. (There are usually bookish prizes!)
Don't let Ms. Reid's alternate personality as the (also extremely helpful!) Query Shark scare you off. I had the opportunity to meet her in person last year at a writer's conference, and I can tell you that she's just as straightforward and utterly helpful in person as she is on her blog.
Oh, and if you're looking for a writing community, check out the comments on each post. There's a whole group of regulars who follow each others' efforts and add funny and interesting dialogue to the posts. Read along for a while and then jump in if you feel so inclined—they're a super-friendly group of people!