This article is what I wish someone had written for me 100 jury charges ago, before drafting my first charge, answering key questions like “where do I start?” and “what next?” There is no one way to do it, certainly, but here is what generally works for me.
First, gather the live pleadings; any summary judgment/dismissal orders; and discovery responses addressing damages theories (disclosures, expert reports, etc.). With these you can determine the range of possible claims, defenses and issues remaining for trial.
Second, determine what purpose your document will serve. Get the judge’s specific requirements, if any, from the court’s website or scheduling order. If the court ordered an exchange of drafts before trial, your task may simply be to get something resembling a charge to opposing counsel by the deadline. If the court wants a proposed joint charge to work on during trial, that may demand more effort. If the draft is for the charge conference, or if it is part of a pretrial order under Federal Rule of Civil Procedure 51, you need a very precise product. In state court you might prepare the document following Texas Rule of Civil Procedure 276.