What would BF members say are the most important things to first learn about Knives, for someone who is just getting into them at the age of 18. (blade steel, locking mechanisms, etc)
This "someone" is you I take it?
My advice (some have already been offered)
1) Buy what you like or knives that are designed to do what you want/need to do.
1a) Be honest/realistic when figuring out what you want to do with your knives
2) Don't get hung up on steels, you won't know the difference anyway at this point. AUS-8, VG-10 stuff will be fine. They still are for me.
3) Don't get hung up on locks. Get a slipjoint like a Victorinox Swiss Army Knife, learn how to use it, and you will never have to worry about lock strength.
4) Cut down.
5) Learn to sharpen on a stone first,
http://www.baryonyxknife.com/no2coinst.html
then you wont have to rely on gadgets.
6) Keep your knives reasonably sharp.
7) If you are even thinking about lock strength/reliability when cutting something, go to a fixed blade.