The basics. Without them you have nothing. Any veteran can tell the difference between some backyard wannabe doing flips and somersaults and a wrestler that knows what he is doing inside the ring. Believe us when we tell you, once you are labeled as a backyard wrestler...it is very very hard to wash that reputation away.
Just because we call them the basics does not mean there is not a lot to learn and practice...
traditions of the ring
running the ropes
hitting the turnbuckles
bumping (landing)
basic wrestling holds and locks
basic brawling techniques
basic slams
communication with referees and timekeepers
basic match psychology
interview skills
As much as pro wrestling can be a blast, it is about business...making money. You are going to have to learn how to make money and save it wisely.
road trips
merchandise
getting paid
Nothing is worse than seeing a greenhorn (new guy) get taken advantage of by a shoddy promotion. To learn the ways shysters can take advantage of you is the best way to avoid them. Learn the signals that can tip you off to a bad promoter and save your body and wallet.