So now you’ve worked everything out in your head, write the damn thing!
Regard this as the creative “anything goes” phase, and get the story down on paper. Don’t worry about making it perfect, or following the rules, just get the words out!
Keep in mind a few key things: make sure it is the character’s voice coming through, and “Show, Don’t Tell” and make it yours.
A really useful book I’ve found is “The Emotion Thesaurus-A Writer’s Guide to Character Expression” by Angela Ackerman and Becca Puglish. It gives you key emotions e.g. contempt,envy, frustration and lists the physical signals that a character feeling that emotion may show. Very useful!
Once in a while stop, and read it out loud as if you were reading it to a child. A lot of the mistakes will come to light, trust me!
As you’re writing promise yourself a nice treat for when you’ve finished. Go on, you deserve it!
And then read this: