Villa skipper Vlaar full of praise for defensive partner Clark
The pair have come together this season and impressed despite Villa's problems.
"The partnership with Ciaran is good but I think we have to improve, for the team and for ourselves," he told the club's official website.
"Communication can always be better and we talk to each other a lot about moments in the game, situations that have happened and what can happen in future.
"I think everybody has to improve. It is a long way but we have to keep it up and move forward."