Fostoria was a customer-savvy company, one of the first to recognize the advantages of solid marketing to go along with beautiful, quality glass products. One example is how they sold many of their blanks (pieces without decoration) as well as the decorated lines. One pattern that you might run into is Lafayette, made from the early 1930s to about 1944.
This divided dish is a good example. See the pretty scalloped, open handles and the subtle optic and slightly scalloped shape.
Here’s a little sweetmeat, aka candy dish. We have this now in topaz yellow and earlier had it in pink.
Lafayette is a lot like Fairfax, especially the plain pieces. Here is a Fairfax cup and saucer. See how the shape is similar to Lafayette, but a little more angular.
The optics are different too, but it can be hard to tell. The easiest way is to check for a curvy shape vs. an angular one with plates or bowls. Or check the handles. Here is the handle to the pink Lafayette sweetmeat.
Also, be aware of the decorations Fostoria used on each. Fairfax was their workhorse during the 1930s, used for etchings like June, Trojan, Versailles. For some reason Fostoria didn’t use Lafayette for many decorations, Fuchsia is the most common etch.
What you will find is color. Fostoria made Lafayette in green, blue, amber, clear, even some ruby and amethyst in addition to the pink and topaz you’ll most often find. The colors are lovely and look wonderful with these elegant, simple curvy shapes.