Alternating engine power for taxy
 

On a standard airliner (let's say 737), Is alternating thrust to help taxi common practice?

Oh, and are brakes on these aircraft toe brake systems?

No and Yes.
Standard practice is to apply power evenly and wait until the aircraft begins to move, then idle power is generally enough except on slopes. Toe brakes are used to slow down for corners or to reduce speed.
Differential power/brakes need only be applied for tight turns, generally 180 degrees or more.