Is plotting really necessary for your proposed novel?
Patrick Ness (A Monster Calls) writes that he always begins by writing the last line first. I could never do that. I like the voyage of discovery in the writing process too much to prescribe an ending. I like an element of surprise. After all, I am putting my characters through the mill and during this they will develop and change and sometimes surprise you with their reactions to events.
Nevertheless if you want to interest an editor or agent you need a plot. Recently I submitted a detailed six-page plot outline to my publisher for a new YA novel. However, it's a plot outline with no flesh on the bones: a character may do something horrid to someone and they will react but, until I write it, I don't necessarily know quite how the character will react. An editor doesn't need to know that. They need to know if it will be exciting and different (but not too different). They will want to know where there will be action or emotion and how the story will be resolved. You will have to work all that out before you pitch, even if you start your pitch with a simple 'Boy meets girl, girl prefers another boy... who claims to be a alien.' (No, I'm not actually writing this.)
The idea is that you are dealing with consequences. The boy will seek to disprove the other boy is an alien and the more he does that the more the girl will like the alien...
A good editor will be one step ahead of you and ask detailed questions: Where is the alien from? What are his characteristics? What makes him so special? Why does the girl prefer him? Don't pitch until you are ready with the answers. The last thing you need is to have the editor interested at the beginning and then feel deflated because you don't know how it all will turn out.
I love character interplay and the mechanics of a relationship. It's also imperative to let characters fail. Take risks. A reader might be disappointed but then will be rewarded when your character picks themselves up and tries again.
Plots are pathways to a resolution, but the strength of a good plot comes from the characters: readers like the characters so much they want them to succeed, and care less about where the characters are going than being able to go with them.
Sometimes when writing you can trap yourself in a corner. Do you go back and rewrite or do you write on? Raymond Chandler always knew what to do: have someone kick down the door with a gun in their hand. Don't worry if things get difficult. Rescue is at hand, even if it's a 'Sorry, wrong door.' I think creating difficulties for yourself is good for the writing. The reader is doubly rewarded when you finally figure it out.
What point in your story should you begin your novel?
The most obvious answer is 'the beginning' but sometimes it's good to start half way in: Your character is trapped in a cave, fire is blocking the entrance and something or someone is approaching that means to kill him. He wishes he hadn't left home at all because any moment now he is going to have to fight to the death, and death is the easy way out. Now you can go back to the beginning. Last Tuesday. It's raining and your character gets a text that simply says, 'Help me. If you love me at all, you will come'.
Readers will have the patience to go along until your character is standing in that burning cave facing the prospect of death. Let's hope your character knows how to survive.
Sam Hawksmoor - author 'Another Place to Die: Endtime Chronicles'