Probably the biggest mistake coaches make when it comes to training a setter is...
Most coaches don't care how the setter gets to the ball. They just want them to get to the ball as quick as they can.
Ignoring Footwork is Big Mistake
Just like you need consistent footwork for approaching to hit, you need consistent footwork for getting in position to set.
When you train the feet, you focus on using a consistent footwork pattern for getting in position. For setting, position is critical because if you can't get into the position, then you can't set the ball.
When setting, you want to always finish the steps left-right. So, if you take 4 steps, the last 2 are left-right.
Finishing left-right allows you to stay open to pass and then make a right turn into the ball. The setter is constantly making right turns on the court. You are always turning to the right and squaring up the left front attacker. Always finish squared to the left front attacker no matter what... even when setting the ball to the middle or setting the ball back.
The more consistent your footwork, the more consistent your set location will be. This is the goal. We want to set the ball with consistency. If your setting is inconsistent, then your attackers won't be sure where the next ball is going to be set.
The key to consistent setting is have consistent setting mechanics... this includes consistent footwork.
The following drill helps train setter footwork.