balancing alloy wheels

NE1 know the correct method of balancing alloy wheels? Is it necessary to apply the weights on a particular side of the wheel? Are stick-on weights as good as clipped ones? Obviously I would prefer to have stick-ns applied to the underside of the actual wheel rim, but to be correctly balanced should weights be on the inside / outside edge? Would like to know the best method in order to choose a "garage" that will do it right, some say one thing.... others say another. TYIA.