Technical Communication Consulting as a Business
http://www.ingentaconnect.com/content/stc/tc/2002/00000049/00000002/art00006
  access restricted (by the publisher) to members/subscribers/customers only
  peer-reviewed

Poe, Stephen D.
Technical Communication Online
2002

Abstract:

To be a successful technical communication consultant requires expertise in two critical areas: technical communication and running a small business. The main reason many technical communicators (and many technical professionals in general) fail as consultants is that they focus exclusively on the first aspect and neglect the second. As employees, they are accustomed to keeping current with new and emerging trends in technical communications. However, as employees they have never needed to learn or maintain currency with the myriad of issues involved in running a small business. It requires a balance of both aspects to be successful as a consultant or a contractor.