The Scotland international started his career as a striker, but he has moved into a deeper position in recent times under Martinez at Goodison Park.
Naismith, who has scored three goals in three games this season, has now paid tribute to the Spaniard for helping him to make key adjustments to his game.
"I've been lucky enough to kick on. It's down to confidence. That comes from the manager who allows me to express myself," the 27-year-old is quoted as saying by Sky Sports News.
"He knows my best position and he's given me my chance there. He knows I can get up and down the pitch but if I play wider I maybe lose aspects of my game.
"I grew up as a striker and he knows I still have a knack of getting in the box. He knows I will defend for the team but he still gives me the freedom going forward."
Everton return to Premier League action on Saturday when they face West Bromwich Albion at The Hawthorns.