Marsh delivered a stellar performance in the IPL last year, scoring 627 runs at an average of 48.23, including his highest score in the format with an innings of 117 off 64 balls against Gujarat Titans.
But he has fallen far short of those lofty levels this year, with the 34-year-old accumulating only 155 runs in the first six matches, averaging 25.83.
With a run of three straight defeats leaving Lucknow ninth of the IPL's 10 teams, Marsh knows he needs to find form fast.
"I probably haven't got going. I think you can maybe search a little bit too much at times," Marsh told Reuters.
"I know that I'm probably one or two boundaries away from really getting going and it's about being consistent with my preparations and knowing that it will come."
With only two wins from their first six games, Lucknow are in danger of missing the playoffs for the third year in a row, but Marsh says there is time to turn things around.
"It's a long tournament and we've got great belief that we can challenge the best teams in the competition ... I think if we can put together a full 40 overs as a unit, we're going to be very hard to break," he said.
Marsh played a key role in helping Perth Scorchers win the Big Bash League in January and was primed to play a big role in Australia's T20 World Cup in February-March but a groin injury hampered his campaign.
Defeats by Zimbabwe and co-hosts Sri Lanka sealed Australia's first group stage exit since 2009.
"Pretty much every game is a knockout game with the way that it's structured up ... one failure can cost you a spot in the knockout stage," said Marsh, who did not want to discuss how the squad dealt with the early exit.
"Those conversations have happened behind closed doors," he added.
Marsh said his focus was now on helping Lucknow win their first IPL trophy.
"I've got great faith in this group ... our best cricket is ahead of us," he added.