There are different, competing claims about the origin of the term 'rule of thumb'. I prefer the idea that it stems from the fact that the length from the tip of the thumb to the knuckle is about one inch (or if you're a pilot and you use 1:500,000 charts, about 10 nautical miles).
In any case, they are useful guidelines that make it easier to do something without thinking it through from first principles each time. Here are my top ten rules of thumb for business copywriting.
Getting there one inch at a time
One-half, one-third, one-sixth. The golden rule: half my time is spent researching and interview. One third is spent proof-reading and editing. Only a sixth is spent actually writing. This is a guideline that I used when I wrote computer games (designing, testing coding) and it works for writing too.
1,000 words a day. Factoring in time for research, writing and editing, I reckon on producing an average of 1,000 publishable words per working day - although the work is usually done in stages over a longer calendar period. (There's a story about James Joyce who had written seven words in one day - a highly productive day for him - "but I don't know what order they go in.") Because writing is a subjective, intimate business it is hard to treat it like a company might treat a factory but measuring productivity is vital if you write for a living.
Lots of interviews. I expect to do one interview for every 250-500 commissioned words. Why? See my post on the importance of interviews. Churchill said that the mind cannot absorb more than the seat can endure and I find that telephone interviews pale after about 30-40 minutes so I try to keep them short.
Transcript length. A 30-minute interview yields about 1,000 words of useful transcript and one or two quotes.
Write for the 8th grade. The level you should write to if you want the 'general public' to be able to understand what you write (as opposed to a technical or well-educated audience). You can gauge this with readability metrics. Source: Jakob Neilsen and Hoa Loranger's great new book 'Prioritizing Web Usability'. You can measure readability, at least in crude terms, using metrics such as Kincard and Fog. See my previous post: Tools for writing: readability statistics in Word.
Proof-read (at least) three times. First edit from start to finish for sense. Then from back to front for typos, grammar and passive-elimination. Then word by word, very slowly and read out loud, to tidy up. I use a spelling and grammar checker in addition to this. I also run all my commercial work past a professional proof-reader at some point in the cycle. I have to say that I don't apply this rule to blog posts - not enough time. Articulate is a glass house and I happily throw stones. Sometimes, also, deadlines and stupidity stop me being so rigorous in the real world which is hateful.
Writing for reading. Conversations are about 200 words per minute while talking books are around 150-175 words per minute and slide shows are closer to 100 wpm. These are useful metrics for writing speeches and presentations. Source: Wikipedia.
Writing for radio. Approximately one page of dialogue per minute of a radio play.
60 minutes. Minimum time spent by me faffing around with my blog and email in the morning before I start on any paid work.
15 minutes to flow time. The amount of time it takes to really settle down and concentrate on my work. Psychologists talk about a 'flow state' where you commune with the work you are doing and sort of merge with it to the exclusion of the outside world. This is why concentration is so important (see my earlier post on How to concentrate on writing) and why interruptions are so deadly to productivity. Source: the wonderful, wonderful book Peopleware: Productive Projects and Teams by Tom DeMarco and Timothy Lister.
Business copywriting is a much an art form as any other kind of writing. While it's important to experiment with the tone and voice of your work, these ten rules will help you get your thoughts down on the page.