Striker Welbeck scored twice in United's 3-0 win at Aston Villa on Sunday, his first Premier League goals since a brace at Swansea City on the opening day of the season.
The 23-year-old has struggled to establish himself in the first team at Old Trafford this season, despite the regular absence of Robin van Persie due to groin, toe and thigh injuries, and found the net just once last term.
A month out with a knee problem has restricted Welbeck's chances further in 2013-14, but Moyes felt the need to speak to the forward about his apparent unwillingness to go the extra mile in training to force his way into the side.
And the Scot added that Welbeck need look no further than fellow United and England forward Rooney as a source of inspiration to maximise his potential.
"We said that he (Welbeck) needs to be the last off the training field," Moyes stated.
"Wayne's out there practising his finishing each day, whether it's taking free-kicks, shooting from tight angles or bending them in - whatever it may be, Wayne's practising.
"I said 'Danny, you need to be out there every day finishing, even if it's 15 minutes at the end'.
"He did (take the advice on board) and to be fair he's out (doing extra work). He's a quick boy and all round I think Danny has got an awful lot of attributes.
"He just has to say 'Hey, come on, I'm going to have to take this on to another level'. We're trying to get him to do that."
