He told Everton's official match programme: "You should work on the mental side as much as anything else, but I don't think it's the case that many do. I think a lot of players don't work enough on their states of mind before going into games.
"It is sometimes overlooked - but speaking to someone has really helped me. In a lot of other sports - especially individual ones - sports psychologists are vital.
"I started [individual sessions] after coming to Everton and have someone I speak to every two or three weeks. The conversations are game-focused more than anything. They refresh your mind.
"We talk a bit about family and stuff but it's mainly football. We'll analyse games, look in detail at opponents I am going to play against and discuss ways to quickly get over any mistakes and not let them affect me.
"It is mainly about being prepared and has helped a lot over a period of time."