For The Flash Episode Guide, I'll be using a slightly modified version of the same key I use for The Arrow Episode Guide, which in turn is based off of what I think is the finest episode guide ever written - Doctor Who: The Discontinuity Guide by Paul Cornell, Martin Day & Keith Topping.
Here is the quick rundown. No pun intended.
Plot: A quick summary of the main story.
Influences: Specific media which may have inspired or otherwise influenced a particular episode.
Goofs: Holes in the plot, visible wires during the stunts and other things that don't work the way they should.
Performances: The actors and their craft - how well the characters are played, ignoring how that character may have been differently portrayed in another story.
Artistry: Anything on the technical side of things that is notably well-handled, such as set-design, lighting, sound effects, cinematography, etc.
Flash Facts: Random things of interest and references to the comics.
Technobabble: Pseudoscience terminology used to justify the unlikely and/or impossible things that sometimes happen in superhero shows.
Dialogue Triumphs: Anything the characters say that make you want to put on a cape and fight for justice!
Dialogue Disasters: Anything the characters say that make you roll your eyes or snort in disbelief.
Continuity: Direct references to previous episodes.
Location: If the story is set someplace other than Central City.
Untelevised Adventures: Stories that take place off camera, but are referred to.
The Fridge Factor: How badly the female characters on the show are manipulated by the story in order to make the male characters look better.
The Boomerang Factor: How badly are the heroes manipulated to look incompetent and badly trained compared to whatever villain they are facing off against. Named in honor of Captain Boomerang, who - honestly - The Flash shouldn't ever have any trouble fighting.
The Bottom Line: Is it good or bad? Why is it good or bad? How can they make it better/not make it worse?