The best way is to brew it with strong tea or tea bags, add ice cubes and an appropriate amount of sugar and stir.

Specific methods:

1. Brew tea leaves or tea bags in hot water for 5-10 minutes to get strong tea.

2. Pour the strong tea into the cup, add appropriate amount of sugar, and stir evenly.

3. Add ice cubes to cool down the tea.

4. Finally, add a few slices of lemon or mint leaves and serve.

Notes:

1. Choosing high-quality tea leaves or tea bags can improve the taste of iced black tea.

2. The amount of sugar can be adjusted according to personal taste.

3. Do not use too many ice cubes to avoid diluting the taste of the tea.

4. If you like a more fragrant taste, you can add an appropriate amount of milk or creamer.