I done freelancing for around 15 years but anyone starting out needs to have a lot of drive and tons of self-discipline. You also need a different mindset - not a hobby but a business and your time is precious and chargeable. Be prepared to spend lots of time in hotel rooms too, sure you can work remotely but many large corporates I worked with wanted my time onsite with them too - mentoring their L&D teams, helping connect my courses to their LMS etc....not everything can be done remotely and onsite can sometimes be pretty profitable.
You'll also need a very broad range of skills as others have alluded too - sales tax (VAT), marketing (to sell yourself and showcase your digital portfolio) and crucially be good at building relationships with clients...repeat work is great. I'm also a big fan of multiple revenue streams so if you have a FT job as others have mentioned, I'd build up my client list PT until the numbers can pay your bills. even then I'd still look for income to supplement your earnings.