1. Parody is typically aimed at a specific target
2. Parody uses caricature
A parody exaggerates commonly recognisable traits or features. It creates a visual or verbal caricature that its audience should immediately recognise.An impressionist might do this by taking a real or imagined catch-phrase - the pound in your pocket was associated with British Prime Minister Harold Wilson, for example. A good parody requires accurate imitation of detail.
3. Satire is more broadly ideological.
Satire assumes some intention or purpose - to make a political point or expose a perceived failing. Jonathan Swift's Gulliver's Travels was aimed at various (long-forgotten) political targets but has endured because its broader themes are universal.
4. Parody can be a form of tribute
A parody relies on audience recognition to work effectively. Many parodies are essentially affectionate - or ambivalent - rather than hostile.Some have the collaboration of their target. George Harrison actively participated in the production of The Rutles, a 'mockumentary' about a rock group clearly based on The Beatles.