How can I tighten the chain on my bike to ensure smooth and efficient performance?

To tighten the chain on your bike for smooth and efficient performance, first, shift the gears to the smallest chainring and smallest cog. Then, loosen the rear wheel nuts slightly and pull the wheel back to create tension in the chain. Make sure the chain is straight and not too tight or loose. Finally, tighten the rear wheel nuts securely and test the chain for proper tension and smooth movement.