There are hints under question mark in the corner. More straightforwardly, you get extra dice for:
- putting roof on top of other die
- putting office (monitor icon) on top of other dice (the higher the better)
- putting services (hand with gear icon), so it have neighbors on the sides
- putting bar (drink icon) on the ground. You generally lose additional dice for putting anything on the ground, so it cancels in this case.