Having managed just seven attempts on goal compared to Spain's 17 in their first game, Rosicky believes his he and team-mates must be more incisive going forward if they are to get off the mark in the tournament.
"We have to take the positive things from the Spain game and build upon them," he said. "Everyone played well and sacrificed a lot and we want to continue with this, with fighting and with cohesion. That's what we need.
"We need to show something more in attack. We need to be better in the end situations.
"We know about the situations against Spain where we were unsuccessful, and want to be better next time."
However, Rosicky is expecting Czech Republic to be up against a different brand of football when his side lock horns with Croatia in Saint-Etienne.
He said: "There are differences in the style between Spain and Croatia. The Spanish play tiki-taka football, whereas Croatia are more straightforward.
"Technically they are similar, but Croatia don't make as many passes. Their style is different.
"[Rakitic and Modric] are the driving force of the Croatian team, with one of them at Barcelona and one at Madrid.
"If I get the task of playing against Modric then I will do that. But I will fulfil whatever role the coach gives me."