I second what Baker said. And avoid 3-position training, or else your progress will be rather slow.
Something to consider while you're down in D4 building your team: defense is key! You can win down there with no defense, but once you make it to D3 you really need players who can defend if you want to be a playoff caliber team.
Did you invest a lot in the draft? This is a great opportunity to get a huge star that can lead your team to greatness!