Final answer:
The serving player must announce the score, stating their own score first followed by the opponent's, before each serve in games like tennis or badminton, and serve from the correct side based on whether their score is even or odd.
Step-by-step explanation:
When a player is serving in a game of tennis or badminton, they need to announce the score at the beginning of each serve. The server must state their own score first, followed by their opponent's score. If it is the first serve of the match or if the server's score is even, they will serve from the right side of the court. Conversely, if their score is odd, they will serve from the left side. Specific sports may have variations in these rules; hence, it is important to be aware of the serving rules for the specific sport being played.