My best advice would be to start off by working for an agency - in my area, agencies are absolutely crying out for temp/perm cleaners. Money (probably) won’t be as good as working for yourself with your own clients, but it’ll give you the chance to learn how to clean a wide variety of different homes quickly and effectively, understand which products really work and what equipment you need, and work out whether it’s something you can cheerfully face doing day in day out - some people find it physically too much, others may find it monotonous. Also, as a PP said, you may find there are some tasks you don’t want to offer - I don’t do full-on oven cleans, or iron clothes (happy to iron bedding though).
That’s how I got started, and it was quite an eye-opener. I was really slow compared to the others at first, gradually picked up speed though and lost plenty of surplus weight in the process (bonus)!
Did agency work full time for a few months, then dropped down my hours as I started picking up clients. I was very lucky, as the agency I was working for was happy to get me started by passing me some enquiries they didn’t want to cover. I’m now fully booked with a waiting list, and earning a decent income.
I provide all of my own cloths and products (except special furniture/floor waxes/polishes) and use my own equipment unless asked not to (due to allergies etc).
You’ll need public liability insurance cover, and car insurance needs to be business class. That’s another good reason for starting with an agency, as you won’t have to outlay any business costs before knowing whether or not it’s for you.