For one; a few smacker singles. It needs to be heavy and played everywhere. K-Dot's "DAMN." does this easily. As did the Chronic.
Skippable tracks are acceptable, I know I've skipped plenty of Pac songs on several albums...still the good needs to outweigh the bad.
Sonically, it needs to follow a theme. 2Pac was bad at this, but because he was so varied, it made up for it. On the other hand, J.Cole is known for staying on theme sometimes, too much...we get it, you miss her, you don't need an entire album about her. This of course leads up to the third thing..beats. If it sounds like hot garbage, it doesn't matter what kind of silk you cover it up with, it'll only be good to the purists. Nas is infamous for this. Horrible beats outweighing the good.