No qualifications needed. College degree, passion for tech and decent writing skills. To be a reviewer you have to have an analytical mind. Fanboyism and bias should not cloud your reviews. If you start your own blog or work for smaller blogs, you'll earn less (per article or via ads). If you apply to a channel, it's best if you join as an intern before applying. There was a similar thread by TheLetterD in this section. Search before posting.
*www.thinkdigit.com/forum/career-planning-progression/151568-tech-journalism.html
PS: This is a Career Planning thread, why post in Education? Moved.