The Belgium international claims that under the club's new Spanish boss they are playing "a more Spanish type of football".
Mirallas said: "The major change for me is the language change because I speak Spanish.
"For me it is better, although I was very happy playing under David Moyes because he is a good manager, but Roberto is different because the Spanish style of playing football is different.
"It's easier because I speak Spanish with him and I understand better.
"The Spanish style of football is my type of football and with Roberto it is very different.
"Every day I have spoken with him and it's helped my confidence.
"It's better because under David Moyes I was not as free but now I am on the line (out wide) more under Roberto - it's different but that's what Roberto wants me to do.
"I feel I am more consistent now. I play better and better. The first game I was not so good and felt tired but now my body is excellent and everything is okay."
Everton beat Hull City 2-1 on Saturday, and Mirallas is keen to keep the first goal despite Gareth Barry wanting to claim it after appearing to get the slightest of touches despite being in an offside position.
"I shot and for me it's my goal. Gareth maybe touched it a little bit but I've seen the results on the television and it's my name and my goal," he added.
"But it doesn't matter if the goal is Gareth's or mine - there is not a problem."
Mirallas felt it was important to beat Hull after losing to Manchester City before the international break.
"I am happy because this was an important game for us," he added.
"The ambition for the club this season is to reach the Champions League.
"It is a long campaign and it can be difficult to finish in the top four, but maybe it is possible for us to do it."