Note: The control schemes I will be listing are the ones on the Gamecube version of this game. All versions of this game should have similar controls schemes but they have different names, if I recall correctly.

Strafing is the fastest way to move in this game, so you want to have a control scheme that makes that as easy as possible. The best control schemes to use are the ones with "Move/Strafe" bounded to the Left control stick and "Look/Turn" bounded to the C-Stick. These are Nightfire, Moonraker, Goldfinger, and Goldeneye. It is not recommended that you use any other control scheme.

To strafe optimally, you have to hold the control stick diagonally up/left or up/right. If the control stick is too far left or right, you will notice a significant loss in speed. Strafing optimally is much easier to do on the Gamecube version because the Gamecube controller has notches in the control stick (which you can easily see in this picture: http://imgur.com/HGo3Thr ). Just hold the control stick in the top-left and top-right notch and you should be moving optimally. For the PS2 and Xbox version you want to hold the control stick as close to diagonally as possible. Doing this is the fastest way to move in this game.

Note: Sometimes the alignment for gamecube controllers can be different. If holding up/left or up/right makes you move very slowly and to the side, move the control stick a little more forward until you notice a large speed increase.