Does anyone know of any good, insightful books that offer advice for writers?
I read Chicken Soup for the Writer's Soul and really liked it, but now I'm looking for an interesting read that might help me write better.
I highly recommend The Elements of Style by William Strunk, Jr. It is a must read for any aspiring author or journalist. I also recommend that you look for Writer's Digest Magazine. They have a very affordable subscription rate and give really great advice on improving your writing for your market (whatever that market is).
Just remember, the first rule of good writing style is "Know your audience." If you know who you're writing to, it is easier to write and more likely to be understood and appreciated.
Stephen King's On Writing was both an entertaining and improving read, so I'd recommend that--and he recommends Elements of Style as well, so definitely try to get your hands on that. Kate Grenville has also published a useful little book, The Writing Book, which actually has some prompts and exercises to help you practice and develop your writing.
Remember, though, that the single best way of improving your writing is just to write--and the next best way is to read, vociferously, so that you can learn by example which styles you prefer and what irks you in another author's work.