For this one you need to be doing Premium Deliveries (press right on an order before confirming it to make it Premium, which makes it tougher - reduced times, more cargo, etc). You need to get the best rating (Legend on Normal difficulty, Legend Of Legends on Hard) 10 times in each of the four delivery categories - Condition, Time, Volume, and Misc. You can tell which orders will affect which categories by looking at the symbol to the left of them on the Terminal - they match up to the symbols on your Rating Star. A clock is for Time, a hand with a box is Condition, hands with three boxes is volume and a hexagon with dots around is Miscellaneous.