If you're at a loss for what to do, why not raise a character to level 5? It should help you realize what you're missing.

Why don't you try finishing up the tutorial? You might've mastered the first step, but nailing down the fundamentals is what's important.

Max out all 3 character statistics.

Play a song for 1 hour of prison time.

Max out the Fitness statistic.

Make an on-the-fly defensive coaching adjustment during a game.

Throw a long pass using Maximum Passing.

Spend 3 days total time in solitary over multiple prisons/sessions.

Enter a multiplayer only area.

Craft an item.

Use a customised character in-game.

Complete 1 S.T.A.R. Lab Mission

Equip a new Background Image