Make your request, your desired actions explicit. Yes, yes, yes: we know that.
If you are respecting Tip 1 (Keep it Short) then long-winded e-mails must be replaced with explicit requests or actions: what/how/when as 'so please send the latest market size date by noon this Friday'.
It makes it so much easier to follow-up if your recipient hasn't fulfilled the request.
Actions are more likely fulfilled when clear.
And sometimes if a mail is simply for information, put: no action/s necessary.