The Toffees have been guilty of throwing away points on numerous occasions, with their defending often weak in the latter stages of matches.
Martinez believes that his side are on the right track, but the Spanish boss is frustrated at how easy it has been for opposition sides to score against his team.
"We just need to stop conceding the goals we are and giving points away softly," he said.
"We're halfway through the season and if we have change of mindset we can really take advantage of the second half.”
Everton’s defensive flaws were once again exposed in their most recent contest against Stoke City.
Martinez’s men had established a 3-2 lead in the fixture, but Stoke scored twice late on through Joselu and Mirko Arnautovic to take the three points.
That defeats means that Everton have now won just one of their last six Premier League matches, even though they have put in some credible performances - especially in an attacking sense.
Everton are currently in 11th place in the Premier League table, but they are only four points away from the European places.