Create a superstar and duplicate him thirty times. Then, start GM mode and turn off every superstar while only leaving on the created superstar. The other two brands will be left with the CAW at 20 popularity. Turn on the superstars again in available draft the next week. When they become available, sign them to win the ratings easily.
Send your superstars on trophy dates until their popularity reaches 100. Once it does, it almost always stays there and will only come down a point or two. When all your superstars are at 100, simply maintain the ones at 99, 98, etc. This will give you easy four star match ratings. Have as many rivalries as you can, and a couple weeks in you will get five star match ratings.