Part of the fun of a sports game is cheering on your team and getting a little rowdy. However, it's still important to be respectful of both your team and the opponent's—that's what's meant by good sportsmanship. Here's how you can accomplish that:
We get it: When you're in the game, you've got your eye on the prize. You're focused on nothing other than the competition at hand. You want to win; no, you need to win. Although you may want to channel all your energy into winning, remember to be considerate of the other athletes. Play by the rules. Work with—not against—your teammates, and listen to your coach if there is one. Don't fight with the ref or risk getting disqualified by using crude language or worse provoking injuries.
If do you lose, lose gracefully. Don't point blame or ruin the other team's celebration. Shake hands and say, "Good game" as you and the other players leave the field, rink or court.
If you win, don't gloat. It's great to show pride in your win, just don't do it at the expense of hurting the other team's feelings. Cheering with your team, high-fiving and fist bumping are all appropriate but avoid saying things like "We crushed them!" to your teammates or worse make comments like "You guys really fell apart." or "You handed that to us." (and yes these are the tame versions of this kind of talk) to the other team.
You're wearing your team's colors, face paint and a giant foam finger, belting out the official fight song and napping pics left and right. All well within the standard bounds of spectator etiquette.
What you don't want to do is: yell profanities, throw food or garbage or any objects anywhere whether it's into the stands or onto the field, jump out of your seat, and definitely do not taunt the other team or jeer at or heckle the ref. Remember to be a supportive sports fan, not an obnoxious, offensive jerk.
If you catch yourself exhibiting any of these behaviors a very quick and simple apology is your best bet (if you haven't been thrown out of the game.) "Oh my gosh, are you alright? I'm sorry I got way too caught up in the moment, I'm so sorry I knocked you with my elbow." or "I'm sorry, I shouldn't yell things like that, especially with kids around."
Whether you're in the game or cheering players on, have fun, keep it positive and always show your support for your team! (Geaux Saints!)