The key to effective writing is to keep it simple. Make it readable and you'll find your message is understood first time.
Think about who your intended reader is and what it is that you are trying to say. Don't use language that'll make your reader work unnecessarily hard to understand your message. It's not your opportunity to demonstrate your extensive vocabulary nor is it a chance to show off your great literary talent.
Writing is not usually something that we do for ourselves; it's nearly always aimed at creating a response in a reader. Some writers see writing as an opportunity to impress, showing how intellectual they can be and how expansive their vocabulary is, often at the expense of their readers' understanding. A simple direct message that's clear and to the point is easy for all to understand.
Effective writing is largely about simplicity of expression, accurate content and brief style.
