Hi and welcome
I'll try to answer a few of your questions. For Cadence, the general rule is it's better to "spin" than to "mash". So in other words, keeping it higher is your goal. It saves the muscles in your legs from getting overworked, especially up hills. With that, spinning requires more cardio endurance, which will come with time. I tend to ride in the 85-100 rpm range, depending on what I'm doing. I have a tendency to mash, and have been working on that this season. Last year I rode most of it in the big ring, but then I didn't have anywhere to go for more power. So I'm focusing on staying in the middle ring (I have a triple) and spinning more. It seems to be working.
When approaching a hill I typically start to downshift so I'm spinning faster as I approach. It's amazing how quickly you slow down as you go up the grade. You don't want to find yourself cranking too early up the hill. Also, I've been told that you'll always have more power up a hill sitting than standing, so try to keep your butt on your seat if you can. But there are always times when you need to stand, it just shouldn't be what you do the whole way up a long hill.
For turns, you should have the foot that's on the side that you're going to be turning toward up so you don't clip your foot on the ground (so making a left, left foot up). If it's a steep turn, then you put your knee out a bit though I'm not sure how far is the right way. I've learned to corner by feel pretty much. I'm sure someone else can describe it better 
Hope that helps. Sounds like you're well on your way.
"Only the meek get pinched, the bold survive"