His side won again at the weekend, beating Wolfsburg 0-1 away from home.
His side has won four out of their last five games, drawing the other 2-2 at home to Hertha Berlin.
Despite sitting comfortably at the top of the Bundesliga, Favre still demands his team to improve.
"We show a good mentality on the pitch when we play. That's the most important thing. The players will improve bit by bit", he told the club's website.
Wolfburg manager Daniel Ginczek was gracious in defeat, as his side remain in 11th position.
"We put in a decent performance today against a good opponent. Dortmund have brutal individual quality and at times we were chasing them."