It can also be an extremely frustrating occupation, too. Purely by chance last night, happened on a planet with some VO hot spots in the rings. 50 mins later on the verge of slamming the keyboard... having watched all the YT videos - bright yellow with a hint of black is good, everything else is dud - failed to acquire one asteroid with a core. Even those that looked like they have fissures once hit with a prospector limpet also turned out to be dud. Really had to wonder whether that counts as entertainment - flying around a bunch of rocks at 75% power, mashing the joystick trigger to continuously scan only to come up empty. In the same time, I could probably have driven from St Petersburg to Turin in ETS2 and enjoyed some nice scenery along the way!
That is the nature of DC mining, I'm afraid.
I find the "best" way to do it is to avoid mucking around, searching for suitable roids.
Just drop into the ring about 1000km from the POI, point your ship at the POI and head toward it at full speed, pinging your PWA as you go and using headlook to look around.
Sure, you might miss a DC roid somewhere off to the side but you'll find another one somewhere in front of you sooner or later.
My Python does 380m/sec and I find, on average, 6 DC roids an hour, which means they're (again, on average) at least 150km apart.
Course, that IS just an average.
Sometimes you find them close together, sometimes you don't find one for 20 minutes.
Point is, due to the fact that they're scattered pretty evenly around the hotspot, there's no point in obsessing over finding them all.
Just keep on truckin' and you'll stumble on them eventually.
Alternatively, just build yourself a Mining T9 and go Painite Mining (in a double hotspot) instead.
Just did that with my alt-account, last night, and earned Cr400m in a couple of hours.
Coriolis EDCD Edition
A ship builder, outfitting and comparison tool for Elite Dangerous

At the moment, the only engineering my T9's got is a G2 weapon-focused PDist.
Eventually I'll upgrade it (much) more but it gets the job done.
You just have to stop mining for a few seconds when the PDist runs out of juice or the lasers start to overheat.
+EDIT+
Tool to help you pick a double Painite hotspot: http://edtools.ddns.net/miner