Easy, but takes some time...
a) Pick any team you want...
b) Go to Edit Players, and then edit their stats in every section to 99. (You don't have to do individually, their is one that makes everyone's stats go up)
c) Simulate the entire season, your record should be pretty damn good...
d) Simulate the playoffs slow, you will probably breeze through it, but just in case, go slow.
e) I think once you go to off-season you should unlock the achievement.