Try selecting all the songs from one album, getting info on them as a group (key Command I), checking whether they're tagged as being part of a compilation (under options) and if so, unchecking it. Then reselecting them and checking them as a compilation again.
Also, if the songs have various artists, maybe featured vocalists or MCs, then you may have to ensure that an Album Artist is also tagged for each song. The last major update of iTunes changed some things about tagging that I can't get to replicate consistently, so don't worry if it's driving you insane as well.