Jermaine Beckford scored the game's only goal after 11 minutes at The Valley, and with Charlton defender Dorian Dervite sent off early in the second half, Beckford's goal was enough to seal the victory.
Talking of their 6-1 defeat on New Year's Day, Miller said: "The Championship is an unforgiving league and we were kicked up the backside.
"We had a full and frank discussion after that defeat and today we played as a team. There were some good individual performances but it was about the team performance.
"Although I did think Charlton kicked on with 10 men and we just tried to defend."
Miller praised match-winner Beckford, saying: "Jermaine can score goals. He's a natural goalscorer. I knew him from his time at Leeds and when he's smiling and happy, he's a threat.
"Lately, he's just not had enough games due to injuries. But if you can get him and James Vaughan on the pitch they are a potent threat. The best in the Championship? I don't know.
"There's lots of teams spending mega money but they will certainly do for Huddersfield. They will both score goals."