So I think this could be a helpful thread for noobs like me!
The Palomar knot always worked well for me back in the trout days using mono, but when I went to a fluorocarbon leader, I started losing fish and lures due to breaking off at the knot. We all know what a buzz kill that is. Maybe I was doing something wrong, but when I switched to the [You must be registered and logged in to see this link.] all those issues went away.
FWIW, I use the [You must be registered and logged in to see this link.] for my braid to fluorocarbon connection. I generally try to use a leader about half the length of my rod so the knot isn't yet into the guides when I'm netting the fish.
As for drag settings, I was obviously setting it too tight, but the reason is because I was testing the drag by pulling on the line at the reel and not feeling all the extra drag you get from a taught line going over a bunch of rod guides. I now test the drag by pulling on the line at the lure end so it's taught on the guides and I can feel the true total drag.
So with those issues out of the way, here's what I'm currently using for line and leader - main line is 20 lb Daiwa Samurai Braid (on the recommendation of SP Dan made here). It's noticeably smoother running through the rod guides, which means it casts farther than the PowerPro braid I was using. I like the sensitivity and strength of the braid. My leader is 10 lb Seaguar Blue Label Saltwater Fluorocarbon. After trying no leader and old school mono and fluorocarbon for leaders, the fluorocarbon got more fish. At first the stiffness was a pain when tying knots, but I've adapted and now it's no problem.
I have no idea if this would apply to fresh water and there are lots of more experienced guys here than me, so I'm curious what lines and leaders and knots y'all are using.