Roy Hodgson's side failed to qualify from their group in Brazil, becoming the first England team to miss the knockout stages since 1958.
However, Martinez believes that England's youthful squad can take positives from their style of play at the tournament.
"I was very impressed with the manner that England approached the competition. Looking back at other tournaments, it was the case of trying to progress and go through," he told FIFA.com.
"This time around, it has been a clear approach of: let's try to be ourselves, let's try to find solutions and learn from the experience for the future. If we progress in this tournament, great, if not we'll get the benefits.
"There is a real legacy growing in this new England set-up. I love the eye-to-eye mentality and having a really brave outlook about their performances."
England return to action in a friendly against Norway in September.