A top-selling DVD is not the same as a top selling DVD.
- Use a hyphen between two words that work together to describe a noun, when the compound adjective comes directly before the noun. Tom wore his brand-new shirt.
- Don't use a hyphen when the two words come after the noun. Tom wore a shirt that was brand new.
- Don't use a hyphen when the first word in a compound modifier is an adverb that ends in '-ly.' She decided not to buy the poorly restored painting.