NBA 2K7

easiest way to do these player achievements is with 2 controllers (NOTE: you must use 2 controllers from the beginning of the match and not change sides half way through a match or it nullifies the achievements you have obtained during that particular game)

pick the team which the player is on and half length you think is long enough to achieve the achievement criteria - i used 3 min halfs though some may need longer or less time.

fo Shaq you need 25pts, 12 rebounds (off or def) and 5 blks (shaq's on the miami heat) for rebounds turn out of bounds off then run directly behind your own basket and take a shot, it should bounce off your own backboard and just catch it (doesn't matter if it bounces) - 1 rebound down quick and easy then just repeat for however many you need.
Blocks - have the second controller team shoot from their own half just stand in front of the player with the ball by about a foot and press the shoot and block (Y) at the same time on both controllers - i had a succes rate of about 85% with this method and worked best for me.