Gary Street's outfit are on track as they seek their eighth consecutive championship triumph but McLean has called for drastic improvements ahead of their clash with Wales this evening.
And, despite those convincing victories in the opening two ties, England's skipper insists the Red Roses' mistakes will not go unpunished as the pressure and intensity builds in their remaining games.
"In terms of performances we have a lot to improve on," McLean told The Guardian.
"We have definitely made too many individual errors and that is a big target for us to improve on.
"The longer we retain the ball the harder it is for the opposition to do us damage and that's important in the games coming up against Wales, France and Ireland."