ROTJ:
I don't know if anyone has already mentioned it, but one of my personal little annoyances is when the Gonk Power Droid is being tortured by a branding iron to his feet. The irons never connect to the feet, yet the steam shoots up (from little holes in the feet for the effect).
So please:
1. Let the branding iron actually touch his feet.
2. Make it look like the steam is in the 'shape' of the iron (so not coming from small holes)
3. Maybe an afterglow, when the iron rises afterward.
Note that I'll be happy as a clam with only #1. 2 and 3 are mere suggestions for further rounding the effect.