Some aesthetic concepts of editing include:
1. Avoid cutting between moving images. Use a cutaway to avoid this.Sound.2. Avoid cutting from moving to still images except as a special effect.
3. Avoid closely matched shots. Try not to have the same subject in adjoining shots.
4. Maintain screen direction (do not cut from a shot with one direction of movement to a shot with the reverse direction).
5. Editing is mostly about context. Try to engage the viewer by building unusual relationships between images and themes. Make your editing dynamic.
Compositing
After Effects is the industry standard "compositing" program used to animate graphic layers to create title sequences and special effects for commercials.
As non-linear editors become more powerful, many complex effects can now be done as part of the basic edit, but there is still a place for motion graphics. The wave of the future seems to be in 3-D movement, which After Effects can do to some extent, however there are even more powerful programs that make this easier.
Compositing is most heavily used in designing title sequences and commercials.