This corn is harvested in the "milk stage" when the kernels contain a sweet white liquid. Unfortunately most people do not experience it at its best, because it should go directly from the corn stalk to boiling water. The problem is, as soon as it's picked the sugars start to convert into starches. Today's very sweet white and yellow varieties have been developed to hold their sweetness as long as possible, but it still fades fairly rapidly.
More on Corn.
Unfortunately many available corn dishes are designed and made in Asia, and are simply too small for American corn. Check size when you buy them.
There are two styles of corn eating: "Typewriter style", where several rows are taken out from one end to another, then rotate up to the next few rows, and "Lathe style" where the cob is rotated all the way around as it is eaten from one end to the other. I always use "typewriter style" and have no idea what those "lathe" people are thinking. I always make a second "gleaning" pass to pick up what was missed on the first pass.
Buying: Buy your corn at a local farmer's market of from some other source you know has fresh corn and a high turnover. Pull the husk back a bit at the tip end so you can see the kernels. The kernels should not have too many gaps, should be full and not at all shriveled (which indicates over-age), and there should be no evidence of worm damage (which always starts at the tip). Do not pull off the husks in the store, that will just accelerate the decline in flavor. Pull them off just before cooking.
Buy corn that's mature but not too mature, The kernels should be pushed up against each other but not too hard and the color should still be fairly light. Really large, square, crowded kernels of darker color indicate an older cob that will be tougher and less sweet. Get it home right away and refrigerate it to slow the conversion to starch. Do not peel off the husk or trim the stem until you're ready to cook it. Cook it as soon as you can.
Cooking: Husk the corn, snap off the stem end and toss it into a large pot of rapidly boiling water. Poke the cobs down into the water and keep them turning so they don't have an undercooked side. For medium size cobs about 3 minutes is all it takes, for very large ones maybe 4. Generally, if the water has come back to a boil over highest heat, they are done.