Startup Management Reporting Challenges

Yes, startups are a world unto themselves, and reporting is always going to be a moving target, as you learn what kinds of reporting do and don’t work with the team, and as your business model evolves. But there’s a lot you can do to standardize your reporting right from the beginning, including:
-- Fonts and font sizes
-- What boldface, color, and other text effects mean in your reports
-- Location of titles, timestamps, pagination, and other “metainformation”
-- Consistent use of terminology, jargon, and acronyms
-- Units of measure ($, $K, $MM) and precision
These may seem like small things, but they will go a long way toward making your audience comfortable and familiar with your reports. It will also make life much easier for YOU when you have to do something really material like, say, changing the line items in the Management P&L.

If you do a good job of this right from the beginning, as your enterprise grows and you need to upgrade your accounting or other information systems, that process will go much more smoothly.

Start up reporting should be as simple as possible, and always linked to cash flow. Identify the key drivers, and make sure those are being tracked and direct vs. overhead costs are properly identified.

I absolutely agree with Randy and James.
I would add that setting up a reporting timetable and sticking to it is very important, especially to the "non-financial" people.
Ask the audience (those people who are on the receiving end) regularly if they understand what the reporting is saying. Make sure to ask the management team if the reporting is helping them run the business.
Paraphrasing Randy, get good habits in place early!