Yep, i've discovered while editing that i really suck at dialogue.
It's not the first thing i gravitate towards while writing - i really prefer to write internal dialogue (perhaps because i tend to live in my own head quite a lot?!).
However, i did notice that one of my scenes really lacked impact.
It contained a lot of he did, she did and then, and of course internal dialogue.
So i went back to the beginning of the scene and inserted dialogue - taunts really - (it was a fight scene) and suddenly it felt real, alive and so much better! I was able to delete a good chunk of the internal dialogue because the characters speaking and their reactions to each other, told more about them than the internal stuff.
Do you suck at dialogue, or is this your natural style?
From the Write Practice i found two great articles. One about rumours and another about observations. Even if you are awesome at dialogue, do visit them, they are well worth the minute to read :)