The USA international, who is on a short-term loan from LA Galaxy, has impressed since returning to club.
However, the 29-year-old has said that he can still improve on his game. The Toffees currently have a lengthy injury list, but Donovan believes that is the only thing stopping the Merseyside club becoming a force again.
"With my form, I'm getting there. I don't think I've been at my absolute best yet and I think I have more to offer," said the forward.
"Not a whole lot has changed in the two years since I was here. Of course, every time you lose players like Arteta and Pienaar, there is going to be a difference in quality.
"But the mentality is good and I think we are just a little bit away from being special again.
"If we can get the four or five injured guys back then the manager will have decisions to make and it will strengthen the squad a lot."
Donovan is on loan at Goodison Park for two months.