Being generous with praise and stingy with gossip is a pretty good personality starter kit.

Two habits, both cheap, both compounding in opposite directions. Saying the good thing out loud costs nothing and makes people relax around you. Passing along the bad thing feels like closeness in the moment and teaches everyone present exactly what happens to information near you. People adjust fast on both counts.

Give one specific compliment a day, about something a person did rather than something they are. When a story about somebody arrives, let it stop with you once. Notice how different the same room feels after a week of that.