"We are not doing those silly things any more which cost us earlier in the season," he said.
"We have to keep on thinking positively all the time, whenever we go on a football pitch.
"Earlier this season we were not doing that enough, but right now we are doing it and look at the results."
The Holland forward added: "If we carry on in the same way we will not drop any more silly points and who knows what will happen in the league, the FA Cup and the Champions League?
"We are certainly coming into great form at just the right time."