I'm in the UK and got picked up by my agent in February and I write Literary Fiction. I was lucky enough to be signed off the back of the query and the first 10,000 words and then wrote the novel afterwards although I had non-fiction experience. I'm editing now, ready to go on submission in the next few months.
If you've done everything you can in terms of editing and considering your query letter itself and studying the market to see who is selling what then you could always consider the paid editor route. There are reputable editors and companies around who can give you a structural edit or even just an overview, some very well respected services will also suggest agents to approach.
Alternatively you can treat your agent search like a military operation and really go for it, research the agents, what they sell, who they sell to, what they personally like to read, then make a list, make it a long one, then send your queries out in batches with a spread of different query letters, see which queries work best, build it from there. The business changes so fast that maybe on and off querying isn't the way to go and you just need to get it out more....it only takes one yes!