This is a pretty broad question, but if you are looking for a general guide on how to write there have been a number of books suggested to me.
Writing for Computer Science (Zobel) This is a decent book on explaining the principles on why and how you should write computer science articles. It's very computer science specific, with a bit more emphasis toward databases and operating systems, but I think it's applicable to most technical fields (of which computational linguistics should fall into).
I like this one because it's a general guide to writing that outlines the process and the structure.
Elements of Style (Strunk and White) A commonly-recommended book that a lot of people swear by but I found it a bit too low-level for my liking and actually had a hard time finishing it. A professor described it as "too prescriptive".
Bugs in Writing (Dupre) This is an okay book as a reference manual for improving your prose, but isn't a good guide for figuring out the writing process. There's good advice in this book (and it's actually rather fun to flip through just to learn about various style points) but can be difficult to use as an actual guide.
Style: Toward Clarity and Grace (Williams) I've gotten through a few parts of this book and it gives very specific advice on how to proceed on improving your writing, especially explaining specifically how to introduce ideas in paragraphs, how to flow them together to create longer manuscripts, and how to restructure and correct text so the main ideas come through. As I surmised, it is in fact very analytical and detailed and does describe the rationales behind its recommendations. I think this book is a great resource for those who have some words written, who know they have to make their writing "flow better" or "more clear" but aren't really sure how to do it. It appears to be an especially valuable book for the "second pass" through anything, where you have written down your initial ideas in part-writing, part bullets, and are trying to convert it into a real readable piece of work. (Previously, I wrote: This book was JUST recommended to me and I haven't read it, but it is apparently very analytical and detailed, and outlines the rationales behind why one should write in the way it discusses. In fact, I think there a jab at the Elements of Style in this book where the author laments that "Be clear" is GREAT advice. We all KNOW that. The real problem is, "How is it that I can actually implement 'be clear' in my writing?" However, I haven't gotten far enough to comment on it yet.)
So there's a little about what to read. As for what you should know? Well, that's a more difficult question :)