I am writing a novel wherein there are many characters whose thoughts are key to telling it properly. In an earlier draft, I attempted to have any given chapter told from the point of view of exactly one character, but that turned out to be problematic. Usually it led to chapters I found uncomfortably short, or I would wind up writing mostly about nothing as I forgot that character was no longer important for the current scene.
In my current draft, I decided to go with a pseudo-omniscient narrator to solve these problems. It could only step into one character's head at a time, but it would be able to switch characters mid-scene, if necessary, rather than waiting for a section or chapter break.
Some of the transitions from one character to another have felt a bit awkward, though. Most of the better ones I have involve dialogue; it's easy to switch the frame to another character naturally after that character has just spoken. Are there any other techniques that can make these transitions flow better?