Everton thumped Swansea 3-0 on Saturday.
"That's what happens if you play as a group of individuals rather than a team," Tate said in the Daily Express.
"We have gone away from the team aspect which made us good last season. We need to get back to playing as a team otherwise we're going to struggle like that every week.
"Defensively we tried to do it on our own. We were more concerned with scoring goals than we were about stopping them at the other end."