The post I just wrote is actually the first time I’ve posted something as a project requirement (as opposed to writing one for no reason). All of the project members are expected to write one, and most are new to the process so I produced a list of tips for them:

Keep it conversational and informal.
The blog should read like a stream of consciousness, and is written as if it was whatever comes into your head. In fact that’s the best way to write it, but review it for structure and style. It should still be readable and make sense.
The idea is to have your personal perspective, but include something factual about the project. What you’ve done, but also what you feel about what you’ve done. Ideally it should be prompting more discussion and so people need to 1) have something solid about professional practice to comment on but 2) be given “permission”, so to speak, to provide their own personal perspective. If it’s just a flat report of what you’ve done, this won’t engage, but if it contains nothing concrete then it’s of no value.
Write about disagreements, problems, and so on, but remember that actually this is a project blog, so overall it will be best to maintain a positive report, and not be critical about colleagues, or institutions.
Don’t worry about length. A paragraph is about the shortest you can do, a page (eg 400 words) is about the longest. It’s more important to do it regularly than do a lot each time.
Add the tag bim-hub, and as many others as you will find useful.
I’ve tried to strike the right balance with the post I’ve just done as an example.

Anyone else got any tips for my colleagues on the project?