if ur talking about TV ads, consider:
camera angles: high, low, medium, close-up, long range, etc...
music: happy, sad, melancholy, joyful, etc...adds to the atmosphere
costuming: also adds to atmosphere to promote a product.
setting and lighting: atmosphere again.
dramaticising: think of the recent PS2 ad with the family (tell us the price dad!(repeat...)...TWO TWO TWO CONTROLLERS!)--> sensationalising
caricature: to make it funny, entertaining, therefore more persuasive.
and, as wrong_turn has correctly said, also consider slogans, jingles, and colour.