Know that it’s not going to be easy. Know that it’s going to take a long time to be good or great. Don’t focus on the career climbing. Focus on the getting funnier. The second you are bitching about what another comic is getting you are going in the completely wrong direction. No one is getting your gig or your money.
Keep in mind that you are in for a looooong haul of ups and downs and nothing and something. It takes at least 15 years, usually more, to make a great comic. most flame out before they get there.
And yes, be polite and courteous to every single person you deal with. Not because that will make you a better comedian, but because you’re supposed to do that.