Mirallas, recruited from Olympiacos last August, made an impressive start to life with the Toffees, but his season has been disrupted by a hamstring problem which limited him to just one first-team appearance between November 10 and January 21.
Having returned to fitness, he has featured in each of Everton's last six matches in all competitions.
Moyes feels the 25-year-old Belgium international is yet to really get into his stride again, though.
The manager said of Mirallas: "I don't think he is firing on all cylinders.
"He has not returned the way I would like him yet. He is still getting used to the Premier League and I think he has to create me more goals and score me more goals.
"That is what I am waiting for him to do, and he knows that - I have told him that. We are hoping for more.
"I think his form at the start of the season was excellent and we saw what he was capable of.
"I don't think we have really had that from him since he came back from his injury."
Everton head into Saturday's Barclays Premier League game at Norwich lying sixth in the table, six points off fourth with 12 top-flight fixtures to play.
They are also still in the FA Cup, with a fifth-round replay against Oldham to come next week, and Moyes hopes Mirallas and fellow frontman Nikica Jelavic can both improve their form to help provide the Toffees with some vital cutting edge in the final section of their campaign.
Jelavic, scorer of 11 goals for the Merseysiders last term following his January arrival from Rangers, has netted seven times for them this season and only once since early December.
Regarding the Croatia international, Moyes - for whom striker Victor Anichebe is an injury doubt ahead of the Norwich contest - said: "We need Niki to come back into it.
"He was a big player for us this time last year, scored a lot of goals and did a good job.
"That is what we could with now, him coming up and giving us the goals.
"I don't think we've played too badly - in fact, I think we have played quite well, and in a lot of the games we've maybe just been missing a little bit of the edge to get us the goals."
Everton, winners only once in their last five league matches, face a Norwich side on Saturday who have gone nine top-flight fixtures without registering a victory.
The 14th-placed Canaries were on a 10-game unbeaten run before that, and Moyes thinks their record shows how fine the margins are in the Premier League.
"There is very little (difference) between when Norwich were winning their games early on, and where they are just now," the Scot said.
"I think it can simply be maybe a centre-forward not scoring when he was doing it in the early part of the season, or a simple goalkeeping mistake changing a game.
"The games are so tight and there is very little between the teams."
Anichebe's condition will be assessed after he came off at half-time in last Saturday's original FA Cup tie at Oldham - a 2-2 draw - having picked up a knock.
Defender Seamus Coleman, who has been sidelined by a thigh problem, is back in training but it remains to be seen whether or not he will be involved on Saturday.