4S: SEE, SNIFF, SIP, SUMMARIZE
The first step is to look at each of the four wines. Compare their color and intensity.
Pick up your Margaux and your St.-Julien, one glass in each hand. Tilt the glasses at a 45 degree angle and compare the color and intensity of the wines. Then put down St.-Julien and pick up the Pauillac. Finally, examine the St.-Estèphe against the Pauillac.