Writing about economics, especially econometrics, is tricky business compared to writing about science and engineering… Models are good: here are a few I’ve found so far.
A Guide for the Young Economist by William Thomson, looks most helpful.
Numerical Methods in Economics by Judd is a good model of how to talk about these things.
Global Economic History: A Very Short Introduction by Robert C. Allen seems also a good model of talk.
Deirdre McCloskey’s Economical Writing is designed to help economists write better, but it’s a good guide for any field (almost).
Professor Petcho’s book, How to Write about Economics and Public Policy, is an excellent book, tailored for GRIPS students, suitable for any economics or policy student. Every GRIPS graduate student should have a copy (it’s also available for free download from the GRIPS library e-book section). Again, you should know everything in this book.