The first step is to analyze your writing style, personality traits and abilities in all honesty. If you are a creative person, you will have a very difficult time trying to write technical material. Technical writing is scientific, accurate and fact-based, with no space for opinions or flowery writing. If you take up freelance technical writing, be prepared to write lots of factual material. Technical writing projects are often in relation to user manuals, installation guides, policies and procedures, requirements documentation, reports, white papers, reference documents, contracts, business proposals etc.
While other freelance writing opportunities present lots of creative freedom, technical writing will always be technical. You will spend 70% of your time on research. Hunting for data in lengthy reports, interviewing people from the relevant technical communities and spending hours accessing databases in search of information are all part of a technical writer's job. You might even have to do a lot of leg work, which will depend on the particular assignment. You have to be clear and 100% certain of your sources. Freelance technical writing can be very laborious, and if you are not willing to go the extra mile, you shouldn't work on such projects.
Freelance technical writing is a field for those who love a mental challenge. Technical writers are found in industries such as IT, chemistry, healthcare, engineering, consumer electronics, finance, biotechnology, robotics and aerospace. If you're a person blessed with both a tech-savvy character and a flair for writing, you should definitely specialize in freelance technical writing.