"I watched our last four games last night to see how we can get out of this - and, in my opinion, when the game has been on the line and we're chasing points, I haven't put us in a good enough position to build pressure.
"I've probably tried to score too often.
"And that's hard to say, but that's what's going to make us better."
After leading the competition after round 12, the Dragons sit in 10th needing to win five of their last six to guarantee they will play on in September.
"It's been a tough seven weeks and there's not a lot of confidence in the camp at the moment," Marshall said.
"Looking at the draw and looking at what we've got left, we've got six weeks and we're still a possibility to make the semi-finals.
"And I think it's a real possibility to win five out of those six games, which would hopefully get us in there."
-AAP