I've always found that it's about defining win/win situations. Also, you should make real human connection in the process. If you don't like the person, that's a real issue. It may not be that the person is unlikeable, it may be that you aren't finding a perspective that aligns right.
But yeah, aligning incentives and making friends. Even if they don't go the way you want, you both still had a positive experience and can potentially find a way to work together in the future.
Sometimes there is no win/win.
Give me an example.
I'm sure you can think of a personally meaningful example if you try; have you turned on the news lately? There's a big story that people seem to be having a hard time finding a win/win and people are starving and being killed.
Sadly, that description doesn't even narrow it down to one "no-win" situation I can think of, so your comment is slightly concerning on its face.
I asked as a chance (a challenge even) to reframe an arbitrary situation.
Even the one you mention, at this exact moment, a win/win could be framed around the benefits of stopping the war. While it's entirely reasonable to pick a perspective that focuses on the awfulness that has occurred, looking ahead, a peace deal would benefit all sides. Certainly it's closer to win/win than continuing down the current path.
My point is that the perspective we take is a choice.