A while back, I was involved with a local cable-access fantasy TV show. We had no budget to speak of and could not use complex video equipment, but did manage a few "in camera" effects that were effective and easy to accomplish. I don't know if any of this will apply to your project in a practical way, but it may give you a few ideas.
Miniature sets and background paintings can add scope to establishing shots and are generally quite easy to build. I liked to add actor presence to these shots by using models. Photo stand-ins (appropriately cut and re-inforced) were even more effective, as they exactly replicated the look of the actors and lacked that shiny model quality.
Since video cameras have a rather forgiving depth-of-field, foreground miniatures can be made to look far bigger than they actually are. I remember building a minature suit of armor for one scene. It was only about a foot high, but when properly positioned in front of the players, it appeared full sized. This can be made to work for live people, too: positioning an actor a few feet closer to the camera will make him seem giant sized in relation to actors farther back. This works best in static shots. Any camera movement usually gives away the illusion.
By employing a black background (we tacked up a specially dyed bed sheet and underlit it), appearing/disappearing tricks can be easily accomplished by sliding dark construction paper across the camera lens, either blotting out or revealing objects. Being out of focus gives the paper's edge a soft, diffused look which aids the illusion.
A sheet of glass or transparent plexi-glass allows ghostly effects to be achieved when placed in front of the camera at a 45% angle to reflect a secondary image off-screen. The secondary set (where the apparition is placed) should be dark as possible. Otherwise, annoying extraneous elements will also be reflected.
Hope these ideas are of some help. Any chance of sharing some of this once you're finished? I'd be fascinated to see it!
