The Tigers are currently in the relegation zone having secured just four victories in 23 games this season.
"The Premier League is where you want to be and the place where you want to earn your corn," Phelan told the club's official website. "But to be here, you have to perform and you have to get things right.
"Effort and endeavour is massive in any game of football and if you step off any percentage of that then you're going to struggle against the best.
"We need to bring a little bit of joy back into it, a little bit of work-rate and maybe a few different things here and there. But there's no secret to it - it's all about the quality of player and making sure that that player is happy and has no excuse not to perform."
Phelan spent five years as Sir Alex Ferguson's right-hand man at Manchester United.