Trapping isn't 100% selective, no matter what set you use, so "versatile" set types will typically yield SOMETHING, whereas not-so-versatile sets will often yield NOTHING, or will leave you with something you didn't want. There are tons of books available, lots of youtube videos available, lots of good and bad (or at least not so good) information in both. Best method is to learn from a veteran, long-lineage trapper - preferably not some dude who bought his first set of bridgers a couple years ago - of course, there's good and bad in their advice too, but it's always best to learn from guys who really KNOW, rather than just learned it themselves last week.
One thing I will say - run WAY more traps than you think you could really use. Some nights you'll almost fill your line with saleable fur, but those nights are few and far between. More often than not, if 10% of your traps strike each night, you're kicking butt. I warned one of my cousins about 5-6yrs ago when he bought 36 footholds, he had permission on about 5 miles of creek line, he didn't have NEARLY enough traps. A season later, he was begging to borrow from my stash of conibears and snares to supplement his lines, then he bought a bunch of my Duke's and all of my coon cuffs from me the next year... He and I share duty on both of our traplines last year and this year, we have over a hundred snares, 40 conibears, I think 6 dozen footholds, and 30 coon cuffs to go into the field in a couple weeks. He's a bit more hard up for cash than I, so he checks weekdays and I check weekends, and I let him keep what he picks up, I keep what I pick up, even though over half of the traps are mine.
Another thing which should be said - learn how to skin and put up your hides properly, and work with your buyers to understand what they want in hides. Some of my buyers over the years have preferred whole carcasses, as they have a team of skilled skinners which do a better job than most trappers/hunters. I've had a guy who flat wouldn't buy head shot coyotes, whereas others preferred it since it meant the usable part of the pelt was without holes. Others want green pelts because their guys can do a better job fleshing than the average trapper. Other guys wouldn't take anything if it wasn't stretched and dried, at least. Get that much work into each hide and you might want to consider putting them up and send them to auction on your own. Or at least consider holding groups which would make good lots to send to auction, even if you need to hold it over a season or two to get a big enough lot to justify it, then selling the lower quality, smaller stuff locally during each season. I've sent furs up to auction, and taken some in person myself, for me, in most years, or more recent years, it's frankly just a lot easier to sell green hides or whole carcass locally most of the time, and not worry as much about the bottom dollar as I used to.
By the by, a club is your friend. I carry a pistol on one hip when walking my traplines, but I carry a hatchet on the other - the flat side face of the hatchet makes a quick kill, but doesn't break the skull/face bones like the heel edge, which makes skinning more difficult. A truckers' "tubthumper" works very nice as well. "No hole hides" are really easy to sell, easier to put up (no blood to wash), and saves money on ammo.