You do something well, but a thing is good. The exception is verbs of sensation in phrases such as “the pie smells good,” or “I feel good.” Despite the arguments of nigglers, this is standard usage. Saying “the pie smells well” would imply that the pastry in question had a nose. Similarly, “I feel well” is also acceptable, especially when discussing health; but it is not the only correct usage.
List of errors