You don't have to have show-quality dogs. You just have to know how to place a pattern correctly, or scissor a non-sporting (poodle/bichon) correctly to hide its faults and emphasize its good points.
For example, my poodle has a short neck. To make it appear longer, I do the body as tightly as I can, especially tight on the sides of the neck, make the topknot a little taller, etc...or I can grow it into a puppy spray-up type of topknot, you name it. Sometimes you have to "build a butt" onto a dog that doesn't have one, etc...
If you have a fox terrier that has a longer muzzle than skull, you can lengthen the brows a bit to make them appear equal in length...
This make sense?
Good luck, I am working on my certification through ISCC and it has been very challenging but I have learned a LOT.
Tammy in Utah
Groomers Helper Affiliate