Enable half-star rating in iTunes
The song rating system that's included in iTunes is useful for users, but it is also limited to only 6 levels: 0 to 5 stars. Since iTunes does not have options for rating songs negatively, users have resorted to giving only one or two stars for songs they do not like, which leaves only three possible ratings for the remaining songs. Some users might enjoy more options for grading their songs. iTunes does support this in terms of half-star ratings, but by default it is turned off. This is presumably for better integrating with other iTunes features such as smart playlists which do not support half-star ratings, but despite this, users can enable it by the following steps:
Quit iTunes Open the Terminal application (in the Utilities folder) Enter the following command in the Terminal
defaults write com.apple.iTunes allow-half-stars -bool TRUE
When this is done, users can open iTunes and rate the desired songs either in the iTunes main window (under list view) or in the song's "Get Info" window. Note that setting the rating via contextual menus or the iTunes menus will not allow for half-step ratings, as these are hard-coded to rate in full-star increments.