drive a hard bargain = not concede much in a negotiation: "He drives a hard bargain. You'd better make sure you're well prepared."

not take no for an answer = not give up even when you are refused something: "She's a tenacious person. She won't take no for an answer."

hold all the aces = have more advantages or strong points than the other party: "It's going to be difficult to negotiate on price with them. They hold all the aces."

have an ace up your sleeve = have a strong negotiating chip in reserve: "What they don't know is that we have an ace up our sleeve in terms of order fulfilment."

to strike a deal = come to agreement: "We finally struck a deal late last night."

a sticking point / a bone of contention = a point that is difficult to agree on: "Unfortunately, salary increases are a sticking point with us."

to get bogged down in detail = become sidetracked by small details: "We aren't getting anywhere at the moment. I suggest we move on to the bigger picture so we don't get bogged down in detail."

play for time = use a delaying tactic: "They're just playing for time at the moment."

play your cards right = use your strong points carefully: "If we play our cards right we could get some good concessions."

sign on the dotted line = sign an agreement: "Well, we finally signed on the dotted line."