Martinez planning to add three attackers
Martinez secured the services of veteran midfielder Gareth Barry on a permanent basis after a successful loan spell at Goodison Park last term, but the Spaniard is in need of attacking reinforcements following Romelu Lukaku's return to parent club Chelsea.
Steven Naismith, Kevin Mirallas and Arouna Kone are the only recognised forwards at the club.
And Martinez is aware he needs to fill the void left by Lukaku, who scored 15 goals in 31 league appearances as Everton finished sixth in 2013-14.
"We want to bring in three attacking players," Martinez told the Liverpool Echo.
"We feel that we are OK in terms of goalkeeper and defence, but we definitely want one midfielder and three attackers."
Martinez added: "You have to plan for the summer well in advance, and we are very happy with the work we have put in since January in preparing for this summer.
"We've worked hard to identify the type of players we want, and we are confident we will be in a good position to strengthen our squad before the end of this window."
Martinez is also prepared to dip into the loan market again, just as he did with Lukaku, Barry and Barcelona youngster Gerard Deulofeu.
"Our use of the loan market has been a strength in recent years," he said. "That is something we will once again look to.
"The loan players that have left were very influential for us last season.
"But we cannot forget that we have a lot of young players already at the club as well. I have been very impressed by some of those players, and we want to have a look at them over the pre-season. Overall I'm positive where we are at."
Everton's first match of the Premier League season is away to newly promoted Leicester City on August 16.