Urgh, you say, 'not more about characters.' lol :) But... It's the plot, characters, and writers voice that will help sell your novel.
I've spent more time in developing my characters as they play a major role in our stories.
I printed out basic character sheets at first, and thought I had it nailed. I was wrong. So I printed out the character interview sheets I have. Wella. I have more rounded characters with pasts that give them reasons for why or how they behave as they do. They are fully developed and have a more of a solid background.
For instance the hero has a son, whose wife died at childbirth. Now we feel sorry for the woman that died, his ex. But...The hero had never forgotten his first love. Ugh you say, 'what type of man marries a woman but is in love with someone else.'
To give the reader sympathy for my hero, his ex wife fell pregnant and they married. He did the right thing. She told him she always wanted children. Six months into the pregnancy she confesses to the hero that she hasn't a maternal bone in her body, that she had never wanted kids. She also tells him three weeks before she gives birth that she is leaving him with the child after the birth. Okay, so now we aren't quite so sympathetic for the ex, but worry about the hero. Poor man. That is rough.
By doing this it has set up more inner conflict for the hero and it will develop into external as the story progresses. If the hero meets someone else how does he know she isn't going to lie to him about children, and how will they act around his six year old son? There are more subplots but this one arrived this morning. I'm quite happy with the development.
I also had a character interview with the heroine and got to know her deeper and the reasons why she reacts in certain ways, and what made her this way. I dug deeper into their feelings. It was a great exercise. So I mustn't forget to make sure I have characters that are real, that have their own mannerisms, and appeal to the reader. (well I hope I have ) :) All this isn't in the manuscript as yet, it is backstory that will be revealed in snippets as the story develops.
If you come to a standstill, stop writing and think. A lot of writing time is spent thinking about the what ifs and you'll come up with good reasons why they act as they do based on past experiences. They say it's often the last idea you have that it's the best. Go with your gut instincts.
Happy writing and/or reading and Never, never, never give up. :)