McLeish is keen to lay down the foundations for years to come as Blues aim to establish themselves in the Premier League.
Christian Benitez, 23, and Scott Dann, 22, have already been added to the side this summer and the boss is hoping to add more youth to his squad ahead of the August kick-off.
"As a club, I think we can improve in a lot of things," McLeish told the Birmingham Mail. "We are, for example, making changes to the training ground so the environment and facilities are better. And of course we are addressing what we need for the team.
"I think in terms of over the last 18 months it has all been a little bit ad-libbed if you like.
"I would like to manage the club for a long period of time having a structure where we are geared up for the next five or six years.
"The way I have worked over the last 18 months didn't really allow for that.
"In order for it to happen we need to bring in four or five younger players. But four or five younger players we feel we can really progress with. It was quite an old team that won promotion, and I'm aware that to go forward we need young, enthusiastic and hungry legs.
"You could argue that two years ago when the team came up there were younger ones, but there was a big lack of experience.
"So it's stepping stones. If we keep bringing the older ones in just to see us through six months or a year - and that's got to be down to my choice as well of course, along with the board - it's hard to get real stability.
"Nothing would give me more satisfaction than Birmingham to have stability in the Premier League."