Casting advice

It may be of some benefit to walk a bit and find a few fish to yourself, if possible, and really try to get the casting/ techniques down at that point, while having a shot at catching some fish. That's not even a rookies only thing, I've been doing this 20 years, and I still would rather walk awhile and find a small pod to myself that haven't been snagged and beaten to death, than combat fish at Manchester hole.
 
As for the crowds, just be aware of your surroundings, and use common sense, and leave plenty of space for you to cast and maneuver. In good faith, most Erie fishermen are good people, and willing to help, and if someone is going to be a jerk about some fish, just don't worry about them, and move on, the problem is with them, not you. If someone is behind you, you may want to wait until they pass in order to cast. When you hook a fish, a good philosophy is that if they fish isn't pulling, you should be pulling it in. This is why drag is so important, you want it to be tight enough that you can control and steer the fish, yet lose enough that it can run, and you can eventually tire it out and get it in.