The Red Roses begin their bid for an unprecedented eighth successive women's Six Nations title and fourth consecutive Grand Slam when they welcome Italy to York on March 23.
Mitchell has tried to rejig the side ahead of the Six Nations, notably by naming lock Zoe Aldcroft as his new captain in place of Marlie Packer.
"We've definitely been a side over the years who have been attracted to consistency, so it's important that we continue to evolve," said Mitchell at Friday's tournament launch in London.
"We've looked at our culture and how that wins very, very strongly. We've made some tweaks in leadership and to the flow of the early part of our week. We've just got started on evolving our game and we certainly want to evolve."
The New Zealander, a former head coach of the men's All Blacks, added: "We'd like to put our opponents under different kinds of pressure as we go into this tournament and hopefully throughout the year we're able to consolidate and then take that into preparation for the home World Cup."
England went undefeated in 2024 and are favourites for the World Cup - which starts in August - where they hope to avenge agonising defeats by New Zealand in the past two finals.