Ha! I'd feel like a fraud if I claimed any credit because it was nothing I did, certainly not deliberately
In January, I put in several very small plants (about 30cm-long, 2 or 3 stems each) of both the lime-green-leaved and purple-leaved varieties, to shade the soil in a new bed quickly over the summer while I decided what to do with it. While I was pondering (I do tend to take a long time pondering), the sweet potato decided it was happy and went on the rampage. Next thing I know, there are giant tubers and they're exploding
They get full sun all day as the garden is south-facing which they love; the soil is clayey but it's good, rich local garden soil newly brought (no rubble or plastic bits) so it wasn't additionally mulched or composted or fertilised. I do water regularly in summer (drip irrigation: hence the sweet-potato-related leak) while I slowly plant ground cover, shade from trees and shrubs etc and removing most of the aspirational English lawn from the south-facing, completely unshaded garden (!) which I inherited when we bought the house three years ago. I am not sure the sweet potato *needs* weekly summer water, but I don't think it could be called drought resistant. Oh yes: snails and slugs love it, although they don't strip it down to the ground, and I don't mind the lacy look too much. The big leaves close to the ground do seem to shelter small moths/flies; not sure what they are but I don't tend to worry too much about insects in the garden unless they wrestle a plant to its knees.
It grows readily from cuttings: no need for anything fancy, just cut off the ends of a vine, trim off the bottom leaves to leave, say, 4 or 5 of the newest leaves at the top, and stick in the soil. It's briefly taken aback for about a week and looks a bit limp, and then gets on with it. A very small number don't 'take', but I have enough so I can just cut some more and plant. The lime-green ones are significantly more vigourous than the purple.
Does this help? I am tempted to say that in our climate it's almost foolproof.