The main skill of a technical writer is the ability to speak with developers and subject matter experts and then translate this information into useful units of information for your audience – whoever that audience may be: developers, network administrators, end users. The style guide will give you a foundation for technical writing, such as how to write about the interface, and what the different interface components are called. Microsoft.com/college is a site that contains great information about the requirements for becoming a technical writer at Microsoft as well as information concerning other careers.