Williams, the D-backs third-base coach, won four Gold Gloves during his playing career.
"He's done it so when a guy like that talks you listen," Bell said.
One of the things Williams preaches is that you field with your feet and not your hands, meaning that if you have proper footwork, the hands will follow.
"I believe it," Bell said. "Feet are very important for everything, just getting you in position to let the rest of your body do the work."
Arizona manager Kirk Gibson said he's noticed a difference.
"We've worked a lot on some stuff, getting him to move his feet a little more," Gibson said. "He just goes about his business, he's very professional."
Bell started for the second day in a row Sunday, the first time he has been in the lineup for back-to-back games since his D-backs debut May 21-22. Bell, who was acquired from the Orioles on April 21, hit .381 in 26 games for Triple-A Reno before being called up.
"It's definitely starting to come, I'm feeling more comfortable just being around the guys," Bell said about settling in with a new team. "That's what I'm looking for, just getting comfortable."