No matter the size or the type of the project, here are some things you might want to consider discussing in your message:
Project context and background, objectives and the creative goal, expectations, call-to-action, challenges, scope, your key message to communicate, your brand voice, your values, your target audience, demographics, competition, your company or stakeholder or client information, responsible persons, client's decision-makers, planned meetings, brand guidelines, what worked in the past for you, examples, references, mood board, style, storyboard, turnaround time, equipment, technical specs, length/duration, quantity, script, subtitles, narrator, product, retouch, edit, effects, location, models or actors or talents or real people, deliverables/outputs, approval process, final product usage, distribution, venues, platforms, rights validity period, length of exposure, campaign budget, payment details.