The key is positivity. Bring people up, not down. If someone is toxic to you, don't spread it. Either ignore, or be even more positive. Try to regularly compliment teammates (and even enemies) after winning rounds or nice shots. Don't troll. Trolling is one of the greatest factors to losing games. Don't make stupid decisions. Try to win, and don't go for the style points. Trust me, this will put a smile on your face and everyone else in the match :D.