How to adjust a Shimano 7-speed rear derailleur?

To adjust a Shimano 7-speed rear derailleur, start by shifting the chain onto the smallest rear cog. Then, use the barrel adjuster to align the jockey wheel with the smallest cog. Next, adjust the high and low limit screws to ensure the chain stays on the cogs. Finally, fine-tune the shifting by adjusting the cable tension using the barrel adjuster.