Communicate with fielders - make sure they know you're on it.

Because you have the best view of the field, and the best line on the ball, you should consider that every bunt you can get to is yours to grab. The only exception - when a player from third is squeezing home.

Charge the bunt and if there's time, get yourself positioned with your head over the ball.

If the bunt is on 1st-base side or back to mound, or towards third on the grass, get your feet lined up for the throw to first before fielding.

Use a scoop technique to block the ball with your mitt and corral it towards the throwing hand.
 
If the bunt is right up the 3rd base line - do a blind side pick up, back to first, and continue to turn counterclockwise to get into throwing position.

Always use a two-hand scoop, even if the ball is dead. (Your eyes may come up at the last second to sight on the runner(s) and you don't want to be groping blindly with your bare hand.)

Throw from low. You don't need to come right up into a full goalpost position, just get your arm back, fingers on top of the ball to start your throw.