The bidding process is a challenge for everyone, and I think most would agree, that it's worth getting right the first time. Guaranteeing this is in large part to a well crafted and thoughtful RFP document.
This RFP, or Request For Proposal should answer every possible question a vendors would have to ask regarding the project requirements, specs, or timeline when evaluating and creating their bid. The goal of your RFP is to prevent follow-up questions as much as possible, so being thorough is a top priority.
Here is a shortlist of data points should be considered for inclusion into your RFP for a commercial production:
Timeline and budget are two big pieces of information that are too often missing or unknown. Despite some apprehension one may have to putting these cards on the table, it will always serve your purpose of not wasting time, and getting appropriate options together if you are forthcoming with budget and timeline. Use your ability to sniff-out foolish bidding to keep your project protected, not omission of critical information.
Any creative needs (scripting, storyboarding, style references, look references, etc)
Casting needs, location needs, pre-production meeting needs, other meeting or progress reporting needs, talent (direct pay by client or within bid)
Number of clients in attendance, video village expectations or requirements, required shoot days (if firm),
Music requirements, required rounds of revisions / cuts, FTP review or in-person, color correction, voice-over, sound design, 2d/3d graphics and/or compositing, visual-Fx
delivery method, resolution, file format, caption requirements, any dub-house specs or streaming service specs
Of course, every project is different and you should never rush this process. It will pay-off throughout the process. An ounce of prevention is worth a pound of cure.