When it comes to writing dialogue, you could do worse than follow the rules of Just a Minute: no hesitation, repetition or deviation. It always amazes me that considering how much cheaper good dialogue is than CGI, stunts, sets, and costumes, it isn’t used to better effect. Theatre scripts provide excellent inspiration for good dialogue, being composed of little else, and having been written with speech at the forefront, without film’s excessive reliance on visual storytelling. I’m particularly fond of the comedy of manners of the turn of the 19th century (The School for Scandal & The Way of the World), and of course, of Oscar Wilde at the turn of the 20th century (The Importance of Being Ernest & An Ideal Husband).
These two dialogue writing worksheets include a table to help you track the conversation in a scene and spot any inconsistencies or mistakes, and a checklist to help you avoid some dialogue writing pitfalls. I hope you find them useful! :)
P.S. I find Ackerman & Puglisi’s Emotion Thesaurus an excellent resource for writing dialogue!