NHL 11

To get this achievement you must have unlocked all the +1, +3, and +5 stats for one attribute. All six slots and boosts can be unlocked in certain ways (which can be looked at by going to the 'EDIT PRO' section) or bought with Microsoft Points. To "buy out" this achievement you will need 720MS points (maximum)! Attach the +1 +3 +5 boosts into those slots into the player, make sure you save and then completely play an EASHL game. Attaching a Boost Pack does NOT work. OTP and Drop-In games will not unlock this achievement.*
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Certain pieces of equipment will only equip certain attributes (although the Helmet and Mask can attach any):
For skaters -
The stick can have: Slap Shot Accuracy, Slap Shot Power, Wrist Shot Accuracy, Wrist Shot Power, Offensive Awareness, Defensive Awareness, Faceoffs, Stick Checking
The skates can have: Aggression, Body Check, Fighting, Acceleration, Agility, Balance, Endurance, Speed
The gloves can have: Deking, Hand Eye, Passing, Puck Control, Discipline, Fighting, Shot Blocking, Strength, Durability
For goalies -
The stick can have: Five Hole, Rebound Control, Passing, Poke Check, Break Away, Aggressiveness,
The trapper can have: Glove High, Glove Low
The blocker can have: Stick High, Stick Low
The pads can have: Speed, Agility, Shot Recovery, Angles, Durability
The mask can also have: Endurance, Vision
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The easiest way to unlock this is probably with a skater (you may find your own way though) and playing through Be A Pro mode for a couple of season as well as you possibly can. This will unlock a good number of the boosts and the slot thus paving away for this achievement. Not too tough but very time consuming.
As a goalie, the easiest one to unlock for me was the Breakaway boosts.

* Thanks to Doc Status' comment.