How can I tighten my bike chain effectively?

To tighten your bike chain effectively, first, loosen the rear wheel nuts. Then, adjust the position of the rear wheel to create tension in the chain. Make sure the chain is straight and not too tight or too loose. Finally, tighten the rear wheel nuts securely. Check the chain tension by pressing down on the chain at the midpoint between the front and rear sprockets - it should move slightly up and down.