The trick here is similar to remembering all complicated formulas in science: Assign some meaning to all letters that make some sense, and is easier to remember. Our formula here is pV=nRT, where p-pressure, V-volume, n-amount in moles, R-Gas Constant, 8.314 (JK^−1mol^−1) and T for temperature in Kelvins. Therefore to remember this formula, I suggest a sentence: "prince William not Richmond Terrier", (of course the V substitute for W might not help, but when you need to remember the sequence of variables, it really helps, as its more about remembering that pV is one side of equation and nRT on the other one .)