England crashed out of the European Championships two years ago with a shock loss to Iceland at the last-16 stage.
Much has changed since then with new manager Gareth Southgate leading a revamped and re-energised squad on an impressive run through this summer’s tournament in Russia.
England will now play Croatia on Wednesday for a chance to secure a place in the final for the first time since 1966.
Speaking at a press conference, midfielder Dier said: “After the Iceland game we knew that things needed to change. There have been a lot of changes since that moment.
“It was a moment where we were extremely disappointed and couldn’t let that happen again. We knew we could only make amends for that moment here at this World Cup. Nothing else would fix what happened.
“That is what we have been trying to do. We have learned from our mistakes.”
England reached the last four with victory over Sweden on Saturday. It is the furthest they have progressed in the tournament since 1990 but Dier insists nobody is congratulating themselves yet.
The 24-year-old said: “I don’t think we have succeeded yet. Success is hard to define but in my eyes, and everyone’s back at the hotel, this isn’t success yet. We’re hungry for more.
“Hopefully we can continue to show that on Wednesday. After the game against Sweden we switched our attention to Wednesday and we are focused on that game.
“We know there can be even better nights the longer we go in the tournament. We have loved every minute, every game, but we know there can be a lot more enjoyment if we continue on this path.”
Team-mate Ashley Young, who carried out media duties on Monday along with Dier, believes England have put themselves in an excellent position but insists nobody is getting carried away.
The left wing-back said: “I think we have got a great chance. We have put ourselves in a great position to go on and win it.
“I said before the start of the tournament we’re not going out there not to win the World Cup.
“But we haven’t won anything yet. There is no point in celebrating. Obviously it was nice to get the victory and the celebrations were muted just because we know there are still big games to come. We know there is a lot to play for.”
Young is preparing for a tough encounter against Croatia.
He said: “Croatia are a very good team. They are not in the semi-final for no reason. We have got to be prepared for them.
“Luka Modric is a fantastic player but they have players around the squad who are going to be difficult opponents.”
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