Boost Super Star Stats:
Press Circle at the main menu to show the active menu. Choose the "Roster" option, then "Edit Player". If your "Create A Player" list has no entries a Super Star player will appear . Press R2 at the edit player screen to increase his stats. Press L2 to return to the "Create A Player" list, then press Start to choose another player.

More Salary Cap Room:
Before starting a new franchise, go to "Roster Mangement". Release your highest paid players to the Free Agent Pool. For example, if you are the Knicks, release Spreewell, Houston, etc.. This also works for any team in the game, so you could release Jordan from Washington, Shaq from the Lakers, etc. and build a super team for the league minimum. Start a new franchise, and go to the "Roster Management" screen. Select "Sign Free Agents" and you can now sign your high priced players back to your team for the league minimum.