The Welshman guided Stoke to their highest Premier League finish and points total last season as City scaled the heights of ninth.
Hughes is eager to build on those foundations but wants to make sure he does not upset dressing-room harmony, having learnt the hard way at former club QPR.
"It's good for the group if you bring in new faces, but you must get the balance right," Hughes told The Stoke Sentinel.
"Sometimes I've found to my detriment that if you make too many changes too quickly it can go against you, and I'm mindful of that.
"We know from the season we had last year that we've got a strong group, so we do not need to make wholesale changes.
"We are adding to the quality we already have and that's important. It's important that the type of player we bring in is correct, not only ability wise but character wise. The group is really strong, and I don't want to upset that dynamic."
Hughes signed 11 players ahead of the 2012-13 campaign at Loftus Road but was dismissed after a 12-game winless run.
In this pre-season he has already signed Mame Biram Diouf, Steve Sidwell, Dionatan Teixeira and Phil Bardsley.
