The 24-year-old has hit five goals in 13 England appearances since making her debut last year and chipped in with an assist in the 2-0 win over Denmark on Saturday.
Neville says she is now ready for the June 7-July 7 showpiece in France but a lot has changed in the last year.
"I think if there's one player I've given the biggest rocket to, it was her and it was in January, over the phone... I said to her, 'Stop being too nice.'
"It's like, 'Do you want to go to Blackpool on your holidays, or do you want to go to the Moon?' She now wants to go to the Moon. Before she was happy to go to Whitley Bay and have fish and chips."
Neville added that the turning point came at the SheBelieves Cup in the United States earlier this year.
Mead came on as a substitute to score the winner against Brazil but was told by Neville she would stay on the bench for England's next match against the hosts.
"She literally stormed out of the room, angry," Neville added. "I thought, job done - she's ready now. She's now beginning to be a player.
"She's tougher. Tougher mentally. She has aggression. She doesn't give up... It's working. But we had to give her some real tough love."
Reuters contributed to this report
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