I have been privileged enough to detect with some of the best and can say they have different techniques, but a few things are apparent with them all. First off is they put in a lot of time behind a detector. Easier for them than most because they essentially are professionals who make or supplement a lot of their income with their finds.
Some barely know the settings on their machines but they know how to get a coil over gold and aren't afraid to dig. Success breeds confidence and confidence is the most underrated and unmentioned tool in the prospectors arsenal. If you see workings or geology which resemble what you've found gold in before, you will stay there and work hard digging trash and covering ground until you find something or are satisfied it's definitely absent. Iffy signals are investigated and trash is less of a nuisance. Confidence gets you back out in the field even if you're working on multiple day skunks. You know it's there and you know you have what it takes so you just keep going.
The last thing I'll mention is their power of observation. They recognize and study all kinds of geological features and old-timer workings which have potential for producing nuggets. Most of them are not educated in geology or mining but neither were most of those gold rush and depression era prospectors. If you spent every day in the field prospecting with a need to feed yourself you'd catch on real quick too. It's like learning a new language, immersion is the best way to learn. Modern day experts are immersed and come to learn the language of the land and gold.
That 10% to 90% ratio appears accurate from what I've seen. It also seems to relate to the fact that I've seen a lot of inexperienced ones spend 90% of their time swinging in ground unlikely to produce whereas the pros spend 90% of their time in the most likely to produce spots. There's more to it than that but it's a big factor.
I should bring out too, they didn't start out successful. Like a professional athlete or really anyone at the top of their profession, they got that way because they worked at it. And like a professional golfer they don't use outdated or inferior equipment. Tiger Woods could still beat any amateur with a wooden driver but when you spend that much of your precious time doing something, it pays to use the best.