You gotta Google.
Stuff like "Deadlift for beginner" and just check out everything you find. I still read and watch videos to find different ways I can improve my form and my overall approach to the Deadlift.
When I started I read up on how to do it, but I'm still finding things that didn't sink in or I didn't quite get
Biggest one for me was grasping how little the Deadlift is like a squat. They are very different but I was starting with my hips much lower than they should have been.
I saw in one of your post the mention of mild scoliosis. If you know the direction of your curve, check out a talk by ed paget(Google his name and scoliosis). He has some great strengthening exercises for scoliosis and keeps in mind not only the curve but the rotation of the spine as well.