I'm generally not a vocal fan but I always made sure that I was more vocally supportive of the team as a whole and other players' good play than of my own. If son or daughter did something particularly well, I would applaud but let others take the vocal lead... unless I had opportunity to make light of things and play down the play or event.
A trick I stumbled upon over time... when engaging in dialog with other parents in the stands, ask a lot of questions about what other interests their player has, about their other kids, about what they like to do away from baseball, etc. After a while, it seems to add balance and perspective to the home bleachers.
Who knew, just being a decent human can be an effective strategy.