You should know that I have been writing fiction for a long time without having anything that was fit to publish. I even worked in Hollywood for a while. (And, I would rather dive into a county fair port-a-potty than do that again.) Anyway, one day I decided to write something that I did want to publish.
My manuscript (by another name) ended up being about 150,000 words long. I sent out queries to many many literary agent in the US and the UK without getting any bites. I finally figured out the reason for this. The main problem was that my manuscript was too long. (Also, the name was too weird.) Most agents, when they see a manuscript of that size from an unknown author, tend to think that the writer does not know how to edit themselves. Furthermore, many agents and publishers feel that the public would not want to commit to reading a book of that length from someone they were unfamiliar with. Agents and publishers like manuscripts that are between 70,000 and 100,000 words from new authors. Yes — there are many excellent books that are longer or shorter than that word count. Go ahead and write one when you get a reputation.
So I re-wrote my manuscript and turned it into two sequential books of about 75,000 word each. This involved 2 beta readers and at least 10 full, careful re-edits of my manuscripts. Luckily, there was a natural break in the middle of the story so everything worked out well.
I then decided to go directly to small and medium sized publishers who accept un-agented work. I immediately got several RFMs from several of them. I picked Bathory Gate Press. They did a wonderful job getting the first book out. Unfortunately, they had to temporarily shut down. Hopefully they will be back up and running soon and I can get my second book released.
I highly recommend sitting down and writing a 100,000 word story if you can manage it. For me, there was a wall at about 50 or 60 thousand words. Up until that point it is pure dreadful torture. But past the wall, it suddenly (dare I say 'magically') gets much much easier. You feel liberation and your story truly starts to write itself.
Note: I have nothing but respect for Flash Fiction. Please. Please don't troll me for saying this. There are many roads to Nirvana.