Unless you are grilling or roasting corn in its husk, strip off the husk and snap off the stems (or leave them on to use it as "handles").
Pull off the silk, which can often become caught between the kernels.

Removing corn off the cob To cut whole kernels from the cob, hold a cob of corn vertically, resting the tip on the work surface. Slide a sharp knife down the length of the cob to slice off the kernels. For cream-style corn, slit each row of kernels with a sharp knife, then run the back of the knife down the length of the cob, to squeeze out the pulp and juice, leaving the skins of the kernels on the cob.

To Boil

You can’t go wrong boiling your fresh cobs of sweet corn but remember that two basic rules apply here:
1. Do not add salt as it will toughen the corn (although a little sugar will enhance the corn's sweetness).
2. Cook the corn only long enough to tenderise it – a matter of minutes.
One method is to add husked cobs of corn to a pot of boiling water, cover it, and let the water return to a boil. Turn off the heat and let stand for five minutes (you can leave it in the hot water for up to 10 minutes).

To Microwave

Put one cob of corn (still in its husk) in the microwave for about 3 minutes on high power.  

To Barbecue or Roast

To roast corn in the husk, remove the silk, then replace the husks and tie them up with kitchen string. Soak the corn in cold water for five minutes. (If the corn is already husked, you can wrap each one in foil.) Place on the grill and cook, turning occasionally for 15-20 mins. To oven-roast corn, place the cobs in a 375°F oven for 25-30 mins.