NBA 2K9

I got this by having my boosting partner intentionally foul me repeatedly until I got A+ grade which doesn't take much. Once you get A+ you can just keep passing out the ball to keep your grade rather than risk dropping it. Just be careful to not make a bad pass for a turnover. The partner can just run the shot clock down to speed things along when he has the ball. My partner and I each got this in one try with this method. Once you finish the game exit to the main menu and then start a search for team mode again to get the achievement to pop. It doesn't pop immediately after your game. We also used a dummy account to avoid risking hurting our main profiles grades. Credit this method to MuddyAmoeba and sm182.

Being given a great player isn't necessarily the best way to achieve this achievement. Nor is it the only way.

I unlocked this achievement playing as a journeyman centre on a team with other good players around me. I set screens and picks, boxed out, defended and rebounded and ended up with an A grade. I barely even scored any baskets.

I've also achieved the A- ranking with a point guard where I kept feeding the ball to the scorers on my team. They got points, I got assists and good passes, and my ranking went up.

The key is to know the position you are playing, to know what is required of you in the role you have within the team, and to ensure you know who your direct opponent is in order to defend him properly.

To earn a positive rating you must obtain what i believe is a A- or better rating playing online. You MUST do this in a Ranked Team-Up game, You are randomly chosen a player on a random team. Everything you do has an impact on your grade. Your best option in getting this achievement is to hope you are given a great player such as Kobe or Lebron.

Positives:
Scoring
Rebounding
Drawing fouls
Assists
Boxing your Opponent out
Good Shot Defense

Negatives:
Bad Shot Selection
Having fouls called on you
Getting boxed out
Leaving your defender open
Allow your man to score
Holding the ball too much

This is just an addition to the very good solutions already out there for this achievement regarding style of play for getting at least an A-.

If you finish a game with at least an A- teammate rating and the achievement does not pop (like it didn't in my case) don't panic. Just go back out the the lobby and start up another team up match. The achievement should pop as you are trying to connect.

Do nothing!

This game is pretty dead online so You need a boosting partner who will just sit and do nothing. This will give you 4 on 4 AI . You will be teamed up against the booster so defending against them should not be an issue. -EDIT- This I have noticed is not always the case, if you end up defending an AI don't try anything tricky just stick on him and defend the best you can. Wait for your opportunities they will happen.

Now to score good points sit on the half way line wait for the AI to get the rebound and feed it to you so you can run the break. Also when you have the ball pass to the open player.

Like the other solutions say you get positive for assists good shot selection not fouling not letting your player score etc. Don't try to take on the AI just run around waiting for a clear shot.

My booster actually got the good teammate by doing nothing.
Its also worth noting the achievement didn't pop for me until I started another game after already averaging A- after 5 games.