I once heard Hillary Swank say in an interview: “Luck is when preparation meets opportunity.”
So you have to be ready when the opportunity comes along. I am currently doing a casting for SNIPER RELOADED, for which all casting is happening online and actors have been asked to put themselves on tape.
There is a whole chapter about this in my book, Secrets from the Casting Couch.
But here are some guidelines. Please click here for HINTS ON SELF AUDITIONS