Negotiating skills and questions

Obviously negotiation is important in this field, but can someone provide examples of what that looks like? Like what are examples of things that you might negotiate?

Do you primarily negotiate through meetings or through written communication?

I’m just curious because as an entry level person, I don’t really have much experience negotiating and have a hard time picturing what that looks like. Do you use what contractors say and propose to get more out of other contractors?