The manager said his team, after 41 and 43 goals in successive Premiership campaigns, must improve their creativity and score more.
Official statistics show that Blues had the least number of shots on target than any Premiership club this season (180), and only relegated Leicester City had fewer attempts off target.
When it came to corners, Blues total of 186 was the fourth worst.
"We know what we've got improve upon," said Bruce, who has signed or targeted threatening players like Emile Heskey, Muzzy Izzet, Julian Gray and Jesper Gronkjaer.
"I won't hide from the fact that when we came into this division, with six weeks to get people in after the playoffs, we went down a certain route.
"We could have gone foreign, got loans in, and gambled on people. What we tried to do was assemble a team that was very difficult to beat, uncompromising, a team the opposition wouldn't enjoy playing against.
"My teams will always have that certain air about them, that's my philosophy.
"But I do concede that we have to score more goals, be a bit more creative, if we are going to win those 12 Premiership games you need to win and progress further.
"To do that you need the players who can take you up that next level, players like an Emile, Mikael Forssell and David Dunn who can conjure that bit of something.
"It remains to be seen if things will fall into place, but I'm very confident we will improve in that respect."
Blues had one of the best defences last season - 15 clean sheets - but behind Forssell's 17 league goals, came Clinton Morrison and Stern John with four apiece.
"It's getting that balance right," said Bruce. "We do work a lot on our shape, our formation and making sure we're organised.
"While we are difficult to break down, I realise scoring 41 goals and then 43, that's got to improve.
"I'm not just saying it's down to the strikers. We've got to be better from midfield areas, wide areas. Our midfielders have got to get 15 to 20 goals between them next season, that's the challenge for them."