Criteria: that you are ready and willing to help your child learn, and that you enjoy spending time with them. Full stop.
Lots of myths out there. You don't have to be rich. You might have to make some "lifestyle choices" about living more simply than you would on more income. You don't have to have one full time working parent and one SAHP, though many do do that. Other possibilities are two part-time working parents, single parent working from home, living on benefits (not a route I'd want to follow myself if I could possibly avoid it, but I understand that needs must where the devil drives for some), extended family or friends being "in charge" for long enough for parents to both do sufficient work to keep a roof over their heads... blah blah blah.
You don't have to have been academically successful or well educated yourself. Google "Paula Rothermel, Durham" and you'll find links to her research on home education, particularly at primary level, which showed (I suspect to her surprise as much as anyone else's) that being HE ENORMOUSLY raised the educational and social outcomes for children of what I think she termed "working class" backgrounds, and raised the outcomes for middle class children of well educated parents, but by less of a differential than for the working class ones. In other words, if you are not yourself well educated, or don't consider yourself to be so, then statistically, your child will be MORE better off out of school than the child of a parent with 15 PhDs. It maybe seems crazy that children do better academically and socially out of school than in it, and children of less well educated families do a lot better out of school than they would have done in it, statistically speaking, but that's what Rothermel found.
I think you need to read "How Children Learn at Home" by Alan THomas and someone Pattison. It's really reassuring. It basically says that you really don't need to "teach" children, just be with them and enjoy family life and being out and about, and they soak things up. "Purposive conversation", where children ask "why" questions and that's the launch pad for conversation/reading books/looking things up on the internet together/ going to the library/ ringing a friend to ask for help etc etc. You don't have to have all the answers, just be prepared to help your child find them!
Exams. some HE families do them, some don't. You don't have to do SATS at all, of course, and that's a factor for some families in taking the HE route. Some families do the usual sheaf of GCSEs, and there's plenty of online advice about following the syllabuses and finding exam centres. Quite a lot of HE families DON'T do the usual sheaf of GCSEs. The children are more likely to think "ok, what do I want to do next?" (particular kind of apprenticeship, particular kind of job, university degree, whatever) and then "What pieces of paper do I need to have to achieve that goal?" and then they get the pieces of paper. OU foundation courses are often accepted by universities for entrance rather than needing GCSEs and A levels, for example. HE teens quite often go to an FE college for A levels or other qualifications at that stage.
THe other important thing is that, if you decide not to send your child to school soon after they turn 4, as per most people, that doesn't mean you are committed to HEing them right through. At any stage, if you and they feel like trying school or switching to school permanently, then the LA have to find a school place for them. Not necessarily at the best/nearest/most recently painted school in the area, but they do have to find a place. So you really have nothing to lose!
Hope that helps - keep asking questions