Building a good team
Start a franchise or season. When you get to the season, go into the "Edit" category and select your player. Choose to move the player to another team. You then can have any desired star on your team. After your first season you will lose some players due to the fact you will be over budget, but you can do this trick again. To get better ratings for other players, do the same thing by selecting a player and then editing the desired category up or down.

Get ejected
Hit a player while pitching three or four times and you will be ejected.