It has been a quiet transfer window so far for Arsenal, which has been linked with moves for Celtic left-back Kieran Tierney, Saint-Etienne teenager William Saliba, Real Madrid's Dani Ceballos and Crystal Palace star Wilfried Zaha.
However, Arsenal are reportedly close to signing Saliba in a deal which would see the 18-year-old loaned back to Saint-Etienne until the end of the season.
Speaking to reporters after Arsenal's 3-0 win over Fiorentina at the International Champions Cup on Sunday (AEST), Emery said: "I am patient because we want to choose the best solution.
"Some players are very expensive and we are waiting for this possibility because we don't want now to go to the second line of players. We are waiting and really we have very good young players.
"We are aware we also need to improve some areas in this squad. But I only want to sign three or four players only if we can be sure they are coming to improve our squad.
"There are a lot of names and the club is working. Edu is very close to me every day and also with the Kroenke family.
"I want to send a message to all our supporters that we want to [build] the best squad possible."
While Arsenal try to sign players, Eddie Nketiah has impressed on the United States tour and the 20-year-old continued his fine form against Fiorentina in Charlotte.
After scoring a late winner against Bayern Munich on Thursday, Nketiah netted a brace to lead Arsenal past Fiorentina in North Carolina.
Asked if Nketiah will remain at Arsenal instead of being loaned out, Emery said: "I spoke with him and with the club. He has started with a doubt if it is better for him to stay here with us or leave to play more minutes with another team.
"But we have examples last year of some players who wanted to go away and didn’t play all we wanted. I said to him to first be focused here. If you earn the right to be with us it’s because I can promise you that you are going to have minutes. But in those minutes you need to learn.
"And in the pre-season at the moment he’s playing like we want. The young players who are here, this is the moment for them to show how we can use them to help us in the season."