United have accumulated 23 yellow cards after only seven games this season, with Scott McTominay and Diogo Dalot both one booking away from suspension while captain Harry Maguire and Bruno Fernandes have been booked three times each.
"I know nasty, I know what it is - in that manner, we can progress, sometimes also play a little bit smarter. We have too many bookings and I don't understand," Ten Hag told reporters on Friday.
"We want to play tough, we want to keep the game going... I saw many other bookings where I think, 'Is that necessary?' But I also take it to the players. I have to keep reminding them to play smart but they have to play nasty as well."
United were far from convincing in their 3-2 comeback win over Cypriot minnows Omonia Nicosia in the Europa League on Thursday and travel to Goodison Park needing a swift response to their 6-3 humbling by champions and rivals Manchester City.
Ten Hag warned it would take months for United's players to develop the urgency, intensity and mindset they need to consistently compete with the best teams.
"It is physical. It is mental. It is also sustainability," he said. "It is like a routine, a way of life, and you have to bring it to every training session, in your system, as a squad and an individual player.
"When you have a lack of it in the last years, it is not something that you build or progress in a week or a month. It has to be in your system. It is a demand in top football nowadays. It is quite clear City set the standard in that.
"We have seen it against Liverpool and Arsenal but now we have to do it on a consistent basis. That is what we have to work for now. But it will not come overnight. It will take more than weeks. It will take months."
Centre back Raphael Varane will face a late fitness test to determine his availability for Sunday, Ten Hag said. Maguire, Aaron Wan-Bissaka and Donny van de Beek remain sidelined.
United are sixth in the league with 12 points from seven games, with Everton, on a six-game unbeaten league run, two points behind them in 11th spot after eight games.
