We often speak of writing "style," which in reality is not one concept but four. I recommended Strunk and White's The Elements of Style as a guide to general or "correct" writing style.

That's the first concept of "style." The other three are:

Group or "our" style
Individual or "my" style
Structural style

Group style is the subject today.

A book you may have to consult much more frequently than Strunk and White is the style manual used by the organization you're writing for, the book whose purpose is to make sure published articles are consistent within a publication or among several publications. In recent years, every company I've worked with has adopted The Associated Press Stylebook and Libel Manual as its bedrock decider on matters of style. Within its 300-plus pages you are told:

o Not to use a comma before the and or but in a series--e.g., Attendees were Mary, Martha and John.
o To spell out all whole numbers below 10 and to use figures for 10 and above,
o To capitalize Hades but not hell,
o To use gale to describe "sustained winds within the range of 39 to 54 mph (34 to 47 knots)
o That pingpong is a synonym for table tennis, and Ping-Pong is a trademarked name, and
o A lot of other stuff that seems to cover the Universe As We (Should) Know It.

Be aware that the first rule cited above runs counter to Strunk, who felt the final comma was needed to avoid confusion. I find it interesting that several editors I know whose official arbiter is the AP guide are unaware of its comma rule. (I know this because I've had them insert the things in my copy!)

My first full-time writing job was with a department that had its own style guide. Other than specifying how to treat department and division names and job titles, it had only three rules:

1. Follow Strunk re commas, and
2. Use employe rather than employee
3. Follow the AP Guide for everything else.

In the three years I worked for that company, I never got used to either of the first two rules. But I obeyed them. Group style--agreed-upon usage--is not negotiable. Think about it as good communication manners--and not institutional repression (or cramping) of "your" style.