I didn't hear this advice until after I had started writing with a vengeance three years ago. Luckily, I have always had varied tastes in literature. I cut my teeth on the greats in Fantasy and SciFi and didn't discover Horror until my early teens. I was ignorant of the small press offerings for most of my adult life, so I felt trapped by what the bookstores had to offer. I had my favorite authors and certainly I experimented from time to time, but I found I could read faster than even a dozen authors could get out new books.
A friend of mine suggested I try something different. Historical fiction in the form of a series by Bernard Cornwell with a central character called Sharpe. Cornwell uses fictional characters to guide the reader through actual historical events of note, in this case the Napoleonic Wars. He later expanded the series to cover Wellington's earlier Indian Campaign. Richard Sharpe started off as an enlisted man and was given a battlefield promotion for saving Wellington's life.
But the Sharpe series was just my introduction to Cornwell. He has published 47 books since 1981 covering mostly English History (there is a Civil War mini series). The most recent book is Agincourt and I can't believe I didn't see it coming. You see, Mr. Cornwell loves archers as any Englishman should, and while I am not English, I also love Archers. The battle of Agincourt was made famous by Shakespeare's Henry the V. It was an impressive battle for many reason, and has always been a favorite of mine. Now for those of you who do not like reading Shakespeare (and you know who you are), you can follow the fictional archer Nicholas Hook from 1413 to 1415 and get a genuine feel for what it was to live, love and fight in England and France during that time period.
I've seen whole threads discussing how to write realistic battle scenes, especially as it relates to melee combat. I recommend people quit looking for answer of this type on forums and start reading more. Bernard Cornwell is a master, wether it is individual combat or a whole scale battle with swords or muskets.
Michael Knost put out a great book called Writers Workshop of Horror. It is filled with excellent advice from writers who are all great, but are recognized for certain things such as opening, character development etc. The book is an excellent writing reference for any level of writer. If you have issues with openings, read Elizabeth Massie's chapter, Creating Effective Beginnings. The unspoken message though is to also read some of Elizabeth's work and the other writers that have been recognized by fans, peers and even critics as being particularly proficient in a certain aspect of writing to get a real feel for how those aspects are done.
I recommend that once you feel comfortable with the horror genre, to expand into other genres. Wether you're a writer trying to improve or an avid reader, you won't be sorry if you pick up a copy of Agincourt. Did I mention he was a genius?